diff --git a/.github/scripts/version_check.py b/.github/scripts/version_check.py
index 497194a049..74c57b967e 100644
--- a/.github/scripts/version_check.py
+++ b/.github/scripts/version_check.py
@@ -17,6 +17,7 @@ import os
 import re
 import sys
 from pathlib import Path
+from typing import Optional
 
 import requests
 
@@ -183,7 +184,8 @@ def check_version_number(version_string, allow_duplicate=False):
     return highest_release
 
 
-if __name__ == '__main__':
+def main() -> bool:
+    """Run the version check."""
     parser = argparse.ArgumentParser(description='InvenTree Version Check')
     parser.add_argument(
         '--show-version',
@@ -220,7 +222,7 @@ if __name__ == '__main__':
     # Ensure that we are running in GH Actions
     if os.environ.get('GITHUB_ACTIONS', '') != 'true':
         print('This script is intended to be run within a GitHub Action!')
-        sys.exit(1)
+        return False
 
     print('Running InvenTree version check...')
 
@@ -261,11 +263,11 @@ if __name__ == '__main__':
     )
 
     # Determine which docker tag we are going to use
-    docker_tags = None
+    docker_tags: Optional[list[str]] = None
 
     if GITHUB_REF_TYPE == 'tag':
         # GITHUB_REF should be of the form /refs/heads/<tag>
-        version_tag = GITHUB_REF.split('/')[-1]
+        version_tag: str = GITHUB_REF.split('/')[-1]
         print(f"Checking requirements for tagged release - '{version_tag}':")
 
         if version_tag != inventree_version:
@@ -287,11 +289,11 @@ if __name__ == '__main__':
         print('GITHUB_REF_TYPE:', GITHUB_REF_TYPE)
         print('GITHUB_BASE_REF:', GITHUB_BASE_REF)
         print('GITHUB_REF:', GITHUB_REF)
-        sys.exit(1)
+        return False
 
     if docker_tags is None:
         print('Docker tags could not be determined')
-        sys.exit(1)
+        return False
 
     print(f"Version check passed for '{inventree_version}'!")
     print(f"Docker tags: '{docker_tags}'")
@@ -308,3 +310,11 @@ if __name__ == '__main__':
 
         if GITHUB_REF_TYPE == 'tag' and highest_release:
             env_file.write('stable_release=true\n')
+    return True
+
+
+if __name__ == '__main__':
+    rslt = main()
+    if rslt is not True:
+        print('Version check failed!')
+        sys.exit(1)
diff --git a/.github/workflows/qc_checks.yaml b/.github/workflows/qc_checks.yaml
index 1300d0a8ba..c2eda31970 100644
--- a/.github/workflows/qc_checks.yaml
+++ b/.github/workflows/qc_checks.yaml
@@ -97,6 +97,27 @@ jobs:
           pip install --require-hashes -r contrib/dev_reqs/requirements.txt
           python3 .github/scripts/version_check.py
 
+  typecheck:
+    name: Style [Typecheck]
+    runs-on: ubuntu-24.04
+    needs: [paths-filter, pre-commit]
+    if: needs.paths-filter.outputs.server == 'true' || needs.paths-filter.outputs.requirements == 'true' || needs.paths-filter.outputs.force == 'true'
+
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # pin@v4.2.2
+        with:
+          persist-credentials: false
+      - name: Environment Setup
+        id: setup
+        uses: ./.github/actions/setup
+        with:
+          apt-dependency: gettext poppler-utils
+          dev-install: true
+          update: true
+      - name: Check types
+        run: |
+          ty check --python ${Python_ROOT_DIR}/bin/python3
+
   mkdocs:
     name: Style [Documentation]
     runs-on: ubuntu-24.04
diff --git a/docs/docs/hooks.py b/docs/docs/hooks.py
index 9a5cf2a41b..52e5998e51 100644
--- a/docs/docs/hooks.py
+++ b/docs/docs/hooks.py
@@ -4,7 +4,7 @@ import json
 import os
 import re
 from datetime import datetime
-from distutils.version import StrictVersion
+from distutils.version import StrictVersion  # type: ignore[import]
 from pathlib import Path
 
 import requests
diff --git a/docs/main.py b/docs/main.py
index 3fbe95233d..48b11d06ed 100644
--- a/docs/main.py
+++ b/docs/main.py
@@ -126,7 +126,7 @@ def check_link(url) -> bool:
     return False
 
 
-def get_build_environment() -> str:
+def get_build_environment() -> Optional[str]:
     """Returns the branch we are currently building on, based on the environment variables of the various CI platforms."""
     # Check if we are in ReadTheDocs
     if os.environ.get('READTHEDOCS') == 'True':
diff --git a/pyproject.toml b/pyproject.toml
index 04f341b519..3b6468b327 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -101,6 +101,20 @@ python-version = "3.9.2"
 no-strip-extras=true
 generate-hashes=true
 
+[tool.ty.src]
+root = "src/backend/InvenTree"
+
+[tool.ty.rules]
+unresolved-reference="ignore"  # 21 # see https://github.com/astral-sh/ty/issues/220
+unresolved-attribute="ignore"  # 505 # need Plugin Mixin typing
+call-non-callable="ignore"  # 8 ##
+invalid-return-type="ignore"  # 22 ##
+invalid-argument-type="ignore"  # 49
+possibly-unbound-attribute="ignore"  # 25 # https://github.com/astral-sh/ty/issues/164
+unknown-argument="ignore"  # 3  # need to wait for betterdjango field stubs
+invalid-assignment="ignore"  # 17  # need to wait for betterdjango field stubs
+
+
 [tool.coverage.run]
 source = ["src/backend/InvenTree", "InvenTree"]
 dynamic_context = "test_function"
diff --git a/src/backend/InvenTree/InvenTree/AllUserRequire2FAMiddleware.py b/src/backend/InvenTree/InvenTree/AllUserRequire2FAMiddleware.py
index b00af18fd0..609c55e3c7 100644
--- a/src/backend/InvenTree/InvenTree/AllUserRequire2FAMiddleware.py
+++ b/src/backend/InvenTree/InvenTree/AllUserRequire2FAMiddleware.py
@@ -48,10 +48,13 @@ class AllUserRequire2FAMiddleware(MiddlewareMixin):
 
     def is_allowed_page(self, request: HttpRequest) -> bool:
         """Check if the current page can be accessed without mfa."""
+        match = request.resolver_match
         return (
-            any(ref in self.app_names for ref in request.resolver_match.app_names)
-            or request.resolver_match.url_name in self.allowed_pages
-            or request.resolver_match.route == 'favicon.ico'
+            None
+            if match is None
+            else any(ref in self.app_names for ref in match.app_names)
+            or match.url_name in self.allowed_pages
+            or match.route == 'favicon.ico'
         )
 
     def enforce_2fa(self, request):
diff --git a/src/backend/InvenTree/InvenTree/api.py b/src/backend/InvenTree/InvenTree/api.py
index 9c49a0f72a..5f3eca035f 100644
--- a/src/backend/InvenTree/InvenTree/api.py
+++ b/src/backend/InvenTree/InvenTree/api.py
@@ -18,6 +18,7 @@ from rest_framework.serializers import ValidationError
 from rest_framework.views import APIView
 
 import InvenTree.config
+import InvenTree.permissions
 import InvenTree.version
 from common.settings import get_global_setting
 from InvenTree import helpers
diff --git a/src/backend/InvenTree/InvenTree/apps.py b/src/backend/InvenTree/InvenTree/apps.py
index 751f8eb54b..34f74850a3 100644
--- a/src/backend/InvenTree/InvenTree/apps.py
+++ b/src/backend/InvenTree/InvenTree/apps.py
@@ -131,6 +131,9 @@ class InvenTreeConfig(AppConfig):
         tasks = InvenTree.tasks.tasks.task_list
 
         for task in tasks:
+            if not task:
+                continue  # pragma: no cover
+
             ref_name = f'{task.func.__module__}.{task.func.__name__}'
 
             if ref_name in existing_tasks:
diff --git a/src/backend/InvenTree/InvenTree/cache.py b/src/backend/InvenTree/InvenTree/cache.py
index 04f9a42d92..e9a9ce8b83 100644
--- a/src/backend/InvenTree/InvenTree/cache.py
+++ b/src/backend/InvenTree/InvenTree/cache.py
@@ -2,6 +2,7 @@
 
 import socket
 import threading
+from typing import Any
 
 import structlog
 
@@ -140,7 +141,7 @@ def delete_session_cache() -> None:
         del thread_data.request_cache
 
 
-def get_session_cache(key: str) -> any:
+def get_session_cache(key: str) -> Any:
     """Return a cached value from the session cache."""
     # Only return a cached value if the request object is available too
     if not hasattr(thread_data, 'request'):
@@ -152,7 +153,7 @@ def get_session_cache(key: str) -> any:
         return val
 
 
-def set_session_cache(key: str, value: any) -> None:
+def set_session_cache(key: str, value: Any) -> None:
     """Set a cached value in the session cache."""
     # Only set a cached value if the request object is available too
     if not hasattr(thread_data, 'request'):
diff --git a/src/backend/InvenTree/InvenTree/config.py b/src/backend/InvenTree/InvenTree/config.py
index 9d8a4a3f86..f51cf924d3 100644
--- a/src/backend/InvenTree/InvenTree/config.py
+++ b/src/backend/InvenTree/InvenTree/config.py
@@ -171,7 +171,7 @@ def get_config_file(create=True) -> Path:
     return cfg_filename
 
 
-def load_config_data(set_cache: bool = False) -> map:
+def load_config_data(set_cache: bool = False) -> Union[map, None]:
     """Load configuration data from the config file.
 
     Arguments:
diff --git a/src/backend/InvenTree/InvenTree/conversion.py b/src/backend/InvenTree/InvenTree/conversion.py
index 669fe950ff..295a2e9fbc 100644
--- a/src/backend/InvenTree/InvenTree/conversion.py
+++ b/src/backend/InvenTree/InvenTree/conversion.py
@@ -191,7 +191,7 @@ def convert_physical_value(value: str, unit: Optional[str] = None, strip_units=T
         attempts.append(f'{value}{unit}')
         attempts.append(f'{eng}{unit}')
 
-    value = None
+    value: Optional[str] = None
 
     # Run through the available "attempts", take the first successful result
     for attempt in attempts:
diff --git a/src/backend/InvenTree/InvenTree/exceptions.py b/src/backend/InvenTree/InvenTree/exceptions.py
index 0775f9ac1f..dbb623eb5b 100644
--- a/src/backend/InvenTree/InvenTree/exceptions.py
+++ b/src/backend/InvenTree/InvenTree/exceptions.py
@@ -66,7 +66,8 @@ def log_error(
         data = error_data
     else:
         try:
-            data = '\n'.join(traceback.format_exception(kind, info, data))
+            formatted_exception = traceback.format_exception(kind, info, data)  # type: ignore[no-matching-overload]
+            data = '\n'.join(formatted_exception)
         except AttributeError:
             data = 'No traceback information available'
 
@@ -150,8 +151,10 @@ def exception_handler(exc, context):
 
     if response is not None:
         # Convert errors returned under the label '__all__' to 'non_field_errors'
-        if '__all__' in response.data:
-            response.data['non_field_errors'] = response.data['__all__']
-            del response.data['__all__']
+        data = response.data
+
+        if data and '__all__' in data:
+            data['non_field_errors'] = data['__all__']
+            del data['__all__']
 
     return response
diff --git a/src/backend/InvenTree/InvenTree/filters.py b/src/backend/InvenTree/InvenTree/filters.py
index 423d9347eb..f6371b4fc9 100644
--- a/src/backend/InvenTree/InvenTree/filters.py
+++ b/src/backend/InvenTree/InvenTree/filters.py
@@ -6,7 +6,8 @@ from django.conf import settings
 from django.utils import timezone
 from django.utils.timezone import make_aware
 
-from django_filters import rest_framework as rest_filters
+import django_filters.rest_framework.backends as drf_backend
+import django_filters.rest_framework.filters as rest_filters
 from rest_framework import filters
 
 import InvenTree.helpers
@@ -20,7 +21,7 @@ class InvenTreeDateFilter(rest_filters.DateFilter):
         if settings.USE_TZ and value is not None:
             tz = timezone.get_current_timezone()
             value = datetime(value.year, value.month, value.day)
-            value = make_aware(value, tz, True)
+            value = make_aware(value, timezone=tz, is_dst=True)
 
         return super().filter(qs, value)
 
@@ -192,17 +193,17 @@ class NumberOrNullFilter(rest_filters.NumberFilter):
 
 
 SEARCH_ORDER_FILTER = [
-    rest_filters.DjangoFilterBackend,
+    drf_backend.DjangoFilterBackend,
     InvenTreeSearchFilter,
     filters.OrderingFilter,
 ]
 
 SEARCH_ORDER_FILTER_ALIAS = [
-    rest_filters.DjangoFilterBackend,
+    drf_backend.DjangoFilterBackend,
     InvenTreeSearchFilter,
     InvenTreeOrderingFilter,
 ]
 
-ORDER_FILTER = [rest_filters.DjangoFilterBackend, filters.OrderingFilter]
+ORDER_FILTER = [drf_backend.DjangoFilterBackend, filters.OrderingFilter]
 
-ORDER_FILTER_ALIAS = [rest_filters.DjangoFilterBackend, InvenTreeOrderingFilter]
+ORDER_FILTER_ALIAS = [drf_backend.DjangoFilterBackend, InvenTreeOrderingFilter]
diff --git a/src/backend/InvenTree/InvenTree/format.py b/src/backend/InvenTree/InvenTree/format.py
index 5fc8c546bb..3ee674b216 100644
--- a/src/backend/InvenTree/InvenTree/format.py
+++ b/src/backend/InvenTree/InvenTree/format.py
@@ -107,7 +107,7 @@ def construct_format_regex(fmt_string: str) -> str:
         # Add a named capture group for the format entry
         if name:
             # Check if integer values are required
-            c = '\\d' if _fmt.endswith('d') else '.'
+            c = '\\d' if _fmt and _fmt.endswith('d') else '.'
 
             # Specify width
             # TODO: Introspect required width
@@ -124,7 +124,7 @@ def construct_format_regex(fmt_string: str) -> str:
     return pattern
 
 
-def validate_string(value: str, fmt_string: str) -> str:
+def validate_string(value: str, fmt_string: str) -> bool:
     """Validate that the provided string matches the specified format.
 
     Args:
diff --git a/src/backend/InvenTree/InvenTree/helpers.py b/src/backend/InvenTree/InvenTree/helpers.py
index a6fc33d2d3..18bc1a6a20 100644
--- a/src/backend/InvenTree/InvenTree/helpers.py
+++ b/src/backend/InvenTree/InvenTree/helpers.py
@@ -9,7 +9,7 @@ import os
 import os.path
 import re
 from decimal import Decimal, InvalidOperation
-from typing import Optional, TypeVar
+from typing import Optional, TypeVar, Union
 from wsgiref.util import FileWrapper
 from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
@@ -22,6 +22,8 @@ from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 
 import bleach
+import bleach.css_sanitizer
+import bleach.sanitizer
 import structlog
 from bleach import clean
 from djmoney.money import Money
@@ -124,7 +126,7 @@ def extract_int(
     return ref_int
 
 
-def generateTestKey(test_name: str) -> str:
+def generateTestKey(test_name: Union[str, None]) -> str:
     """Generate a test 'key' for a given test name. This must not have illegal chars as it will be used for dict lookup in a template.
 
     Tests must be named such that they will have unique keys.
@@ -366,9 +368,7 @@ def increment(value):
     except ValueError:
         pass
 
-    number = number.zfill(width)
-
-    return prefix + number
+    return prefix + str(number).zfill(width)
 
 
 def decimal2string(d):
@@ -966,7 +966,7 @@ def current_time(local=True):
     """
     if settings.USE_TZ:
         now = timezone.now()
-        now = to_local_time(now, target_tz=server_timezone() if local else 'UTC')
+        now = to_local_time(now, target_tz_str=server_timezone() if local else 'UTC')
         return now
     else:
         return datetime.datetime.now()
@@ -985,12 +985,12 @@ def server_timezone() -> str:
     return settings.TIME_ZONE
 
 
-def to_local_time(time, target_tz: Optional[str] = None):
+def to_local_time(time, target_tz_str: Optional[str] = None):
     """Convert the provided time object to the local timezone.
 
     Arguments:
         time: The time / date to convert
-        target_tz: The desired timezone (string) - defaults to server time
+        target_tz_str: The desired timezone (string) - defaults to server time
 
     Returns:
         A timezone aware datetime object, with the desired timezone
@@ -1014,11 +1014,11 @@ def to_local_time(time, target_tz: Optional[str] = None):
         # Default to UTC if not provided
         source_tz = ZoneInfo('UTC')
 
-    if not target_tz:
-        target_tz = server_timezone()
+    if not target_tz_str:
+        target_tz_str = server_timezone()
 
     try:
-        target_tz = ZoneInfo(str(target_tz))
+        target_tz = ZoneInfo(str(target_tz_str))
     except ZoneInfoNotFoundError:
         target_tz = ZoneInfo('UTC')
 
diff --git a/src/backend/InvenTree/InvenTree/helpers_email.py b/src/backend/InvenTree/InvenTree/helpers_email.py
index 3d9f21c539..9ee225a506 100644
--- a/src/backend/InvenTree/InvenTree/helpers_email.py
+++ b/src/backend/InvenTree/InvenTree/helpers_email.py
@@ -114,7 +114,7 @@ def send_email(
     return True, None
 
 
-def get_email_for_user(user) -> str:
+def get_email_for_user(user) -> Optional[str]:
     """Find an email address for the specified user."""
     # First check if the user has an associated email address
     if user.email:
diff --git a/src/backend/InvenTree/InvenTree/helpers_model.py b/src/backend/InvenTree/InvenTree/helpers_model.py
index 23a7c71f1c..62710407d8 100644
--- a/src/backend/InvenTree/InvenTree/helpers_model.py
+++ b/src/backend/InvenTree/InvenTree/helpers_model.py
@@ -11,6 +11,7 @@ from django.db.utils import OperationalError, ProgrammingError
 from django.utils.translation import gettext_lazy as _
 
 import requests
+import requests.exceptions
 import structlog
 from djmoney.contrib.exchange.models import convert_money
 from djmoney.money import Money
@@ -328,8 +329,9 @@ def notify_users(
         'template': {'subject': content.name.format(**content_context)},
     }
 
-    if content.template:
-        context['template']['html'] = content.template.format(**content_context)
+    tmp = content.template
+    if tmp:
+        context['template']['html'] = tmp.format(**content_context)
 
     # Create notification
     trigger_notification(
diff --git a/src/backend/InvenTree/InvenTree/management/commands/schema.py b/src/backend/InvenTree/InvenTree/management/commands/schema.py
index ae07c8b41e..22368c74c7 100644
--- a/src/backend/InvenTree/InvenTree/management/commands/schema.py
+++ b/src/backend/InvenTree/InvenTree/management/commands/schema.py
@@ -1,7 +1,7 @@
 """Extended schema generator."""
 
 from pathlib import Path
-from typing import TypeVar
+from typing import TypeVar, Union
 
 from django.conf import settings
 
@@ -26,7 +26,7 @@ def prep_name(ref):
     return f'{dja_ref_prefix}.{ref}'
 
 
-def sub_component_name(name: T) -> T:
+def sub_component_name(name: T) -> Union[T, str]:
     """Clean up component references."""
     if not isinstance(name, str):
         return name
diff --git a/src/backend/InvenTree/InvenTree/management/commands/wait_for_db.py b/src/backend/InvenTree/InvenTree/management/commands/wait_for_db.py
index 6bfdc98b58..68b33adfff 100644
--- a/src/backend/InvenTree/InvenTree/management/commands/wait_for_db.py
+++ b/src/backend/InvenTree/InvenTree/management/commands/wait_for_db.py
@@ -2,9 +2,10 @@
 
 import time
 
+from django.core.exceptions import ImproperlyConfigured
 from django.core.management.base import BaseCommand
 from django.db import connection
-from django.db.utils import ImproperlyConfigured, OperationalError
+from django.db.utils import OperationalError
 
 
 class Command(BaseCommand):
diff --git a/src/backend/InvenTree/InvenTree/models.py b/src/backend/InvenTree/InvenTree/models.py
index 78f0f9774c..7a7368079e 100644
--- a/src/backend/InvenTree/InvenTree/models.py
+++ b/src/backend/InvenTree/InvenTree/models.py
@@ -1172,7 +1172,7 @@ class InvenTreeBarcodeMixin(models.Model):
             raise ValueError("Provide either 'barcode_hash' or 'barcode_data'")
 
         # If barcode_hash is not provided, create from supplier barcode_data
-        if barcode_hash is None:
+        if barcode_hash is None and barcode_data is not None:
             barcode_hash = InvenTree.helpers.hash_barcode(barcode_data)
 
         # Check for existing item
diff --git a/src/backend/InvenTree/InvenTree/permissions.py b/src/backend/InvenTree/InvenTree/permissions.py
index bd77fab42b..bc48d862ea 100644
--- a/src/backend/InvenTree/InvenTree/permissions.py
+++ b/src/backend/InvenTree/InvenTree/permissions.py
@@ -256,7 +256,9 @@ class RolePermissionOrReadOnly(RolePermission):
     def get_required_alternate_scopes(self, request, view):
         """Return the required scopes for the current request."""
         scopes = map_scope(
-            only_read=True, read_name=DEFAULT_STAFF, map_read=permissions.SAFE_METHODS
+            only_read=True,
+            read_name=DEFAULT_STAFF,
+            map_read=list(permissions.SAFE_METHODS),
         )
         return scopes
 
@@ -294,7 +296,7 @@ class IsSuperuserOrReadOnlyOrScope(OASTokenMixin, permissions.IsAdminUser):
         return map_scope(
             only_read=True,
             read_name=DEFAULT_SUPERUSER,
-            map_read=permissions.SAFE_METHODS,
+            map_read=list(permissions.SAFE_METHODS),
         )
 
 
@@ -319,7 +321,9 @@ class IsStaffOrReadOnlyScope(OASTokenMixin, permissions.IsAuthenticated):
     def get_required_alternate_scopes(self, request, view):
         """Return the required scopes for the current request."""
         return map_scope(
-            only_read=True, read_name=DEFAULT_STAFF, map_read=permissions.SAFE_METHODS
+            only_read=True,
+            read_name=DEFAULT_STAFF,
+            map_read=list(permissions.SAFE_METHODS),
         )
 
 
@@ -349,7 +353,7 @@ def auth_exempt(view_func):
     def wrapped_view(*args, **kwargs):
         return view_func(*args, **kwargs)
 
-    wrapped_view.auth_exempt = True
+    wrapped_view.auth_exempt = True  # type:ignore[unresolved-attribute]
     return wraps(view_func)(wrapped_view)
 
 
@@ -400,7 +404,9 @@ class GlobalSettingsPermissions(OASTokenMixin, permissions.BasePermission):
     def get_required_alternate_scopes(self, request, view):
         """Return the required scopes for the current request."""
         return map_scope(
-            only_read=True, read_name=DEFAULT_STAFF, map_read=permissions.SAFE_METHODS
+            only_read=True,
+            read_name=DEFAULT_STAFF,
+            map_read=list(permissions.SAFE_METHODS),
         )
 
 
diff --git a/src/backend/InvenTree/InvenTree/sanitizer.py b/src/backend/InvenTree/InvenTree/sanitizer.py
index 0272b50f94..ce093b96fe 100644
--- a/src/backend/InvenTree/InvenTree/sanitizer.py
+++ b/src/backend/InvenTree/InvenTree/sanitizer.py
@@ -188,8 +188,8 @@ ALLOWED_ATTRIBUTES_SVG = [
 def sanitize_svg(
     file_data,
     strip: bool = True,
-    elements: str = ALLOWED_ELEMENTS_SVG,
-    attributes: str = ALLOWED_ATTRIBUTES_SVG,
+    elements: list[str] = ALLOWED_ELEMENTS_SVG,
+    attributes: list[str] = ALLOWED_ATTRIBUTES_SVG,
 ) -> str:
     """Sanitize a SVG file.
 
diff --git a/src/backend/InvenTree/InvenTree/serializers.py b/src/backend/InvenTree/InvenTree/serializers.py
index 9aa653c1af..59cbb81532 100644
--- a/src/backend/InvenTree/InvenTree/serializers.py
+++ b/src/backend/InvenTree/InvenTree/serializers.py
@@ -373,16 +373,15 @@ class InvenTreeModelSerializer(serializers.ModelSerializer):
             instance.full_clean()
         except (ValidationError, DjangoValidationError) as exc:
             if hasattr(exc, 'message_dict'):
-                data = exc.message_dict
+                data = {**exc.message_dict}
             elif hasattr(exc, 'message'):
                 data = {'non_field_errors': [str(exc.message)]}
             else:
                 data = {'non_field_errors': [str(exc)]}
 
             # Change '__all__' key (django style) to 'non_field_errors' (DRF style)
-            if '__all__' in data:
-                data['non_field_errors'] = data['__all__']
-                del data['__all__']
+            if hasattr(data, '__all__'):
+                data['non_field_errors'] = data.pop('__all__')
 
             raise ValidationError(data)
 
diff --git a/src/backend/InvenTree/InvenTree/settings.py b/src/backend/InvenTree/InvenTree/settings.py
index 092574042c..e5a3f4297e 100644
--- a/src/backend/InvenTree/InvenTree/settings.py
+++ b/src/backend/InvenTree/InvenTree/settings.py
@@ -43,6 +43,13 @@ from users.oauth2_scopes import oauth2_scopes
 
 from . import config, locales
 
+try:
+    import django_stubs_ext
+
+    django_stubs_ext.monkeypatch()  # pragma: no cover
+except ImportError:  # pragma: no cover
+    pass
+
 checkMinPythonVersion()
 
 INVENTREE_BASE_URL = 'https://inventree.org'
@@ -382,22 +389,25 @@ QUERYCOUNT = {
 }
 
 
-AUTHENTICATION_BACKENDS = CONFIG.get(
-    'authentication_backends',
-    [
-        'oauth2_provider.backends.OAuth2Backend',  # OAuth2 provider
-        'django.contrib.auth.backends.RemoteUserBackend',  # proxy login
-        'django.contrib.auth.backends.ModelBackend',
-        'allauth.account.auth_backends.AuthenticationBackend',  # SSO login via external providers
-        'sesame.backends.ModelBackend',  # Magic link login django-sesame
-    ],
+default_auth_backends = [
+    'oauth2_provider.backends.OAuth2Backend',  # OAuth2 provider
+    'django.contrib.auth.backends.RemoteUserBackend',  # proxy login
+    'django.contrib.auth.backends.ModelBackend',
+    'allauth.account.auth_backends.AuthenticationBackend',  # SSO login via external providers
+    'sesame.backends.ModelBackend',  # Magic link login django-sesame
+]
+
+AUTHENTICATION_BACKENDS = (
+    CONFIG.get('authentication_backends', default_auth_backends)
+    if CONFIG
+    else default_auth_backends
 )
 
 # LDAP support
 LDAP_AUTH = get_boolean_setting('INVENTREE_LDAP_ENABLED', 'ldap.enabled', False)
 if LDAP_AUTH:
-    import django_auth_ldap.config
-    import ldap
+    import django_auth_ldap.config  # type: ignore[unresolved-import]
+    import ldap  # type: ignore[unresolved-import]
 
     AUTHENTICATION_BACKENDS.append('django_auth_ldap.backend.LDAPBackend')
 
@@ -450,7 +460,7 @@ if LDAP_AUTH:
     )
     AUTH_LDAP_USER_SEARCH = django_auth_ldap.config.LDAPSearch(
         get_setting('INVENTREE_LDAP_SEARCH_BASE_DN', 'ldap.search_base_dn'),
-        ldap.SCOPE_SUBTREE,
+        ldap.SCOPE_SUBTREE,  # type: ignore[unresolved-attribute]
         str(
             get_setting(
                 'INVENTREE_LDAP_SEARCH_FILTER_STR',
@@ -486,7 +496,7 @@ if LDAP_AUTH:
     )
     AUTH_LDAP_GROUP_SEARCH = django_auth_ldap.config.LDAPSearch(
         get_setting('INVENTREE_LDAP_GROUP_SEARCH', 'ldap.group_search'),
-        ldap.SCOPE_SUBTREE,
+        ldap.SCOPE_SUBTREE,  # type: ignore[unresolved-attribute]
         f'(objectClass={AUTH_LDAP_GROUP_OBJECT_CLASS})',
     )
     AUTH_LDAP_GROUP_TYPE_CLASS = get_setting(
@@ -604,7 +614,7 @@ Configure the database backend based on the user-specified values.
 logger.debug('Configuring database backend:')
 
 # Extract database configuration from the config.yaml file
-db_config = CONFIG.get('database', None)
+db_config = CONFIG.get('database', None) if CONFIG else None
 
 if not db_config:
     db_config = {}
@@ -690,7 +700,9 @@ if db_options is None:
 
 # Specific options for postgres backend
 if 'postgres' in DB_ENGINE:  # pragma: no cover
-    from django.db.backends.postgresql.psycopg_any import IsolationLevel
+    from django.db.backends.postgresql.psycopg_any import (  # type: ignore[unresolved-import]
+        IsolationLevel,
+    )
 
     # Connection timeout
     if 'connect_timeout' not in db_options:
diff --git a/src/backend/InvenTree/InvenTree/sso.py b/src/backend/InvenTree/InvenTree/sso.py
index c1842d70de..cbb2d79938 100644
--- a/src/backend/InvenTree/InvenTree/sso.py
+++ b/src/backend/InvenTree/InvenTree/sso.py
@@ -50,7 +50,7 @@ def check_provider(provider):
     if not app:
         return False
 
-    if allauth.app_settings.SITES_ENABLED:
+    if allauth.app_settings.SITES_ENABLED:  # type: ignore[unresolved-attribute]
         # At least one matching site must be specified
         if not app.sites.exists():
             logger.error('SocialApp %s has no sites configured', app)
@@ -102,6 +102,7 @@ def ensure_sso_groups(sender, sociallogin: SocialLogin, **kwargs):
 
     # ensure user has groups
     user = sociallogin.account.user
+
     for group_name in group_names:
         try:
             user.groups.get(name=group_name)
diff --git a/src/backend/InvenTree/InvenTree/tasks.py b/src/backend/InvenTree/InvenTree/tasks.py
index 9903a04ac0..4e07f75bad 100644
--- a/src/backend/InvenTree/InvenTree/tasks.py
+++ b/src/backend/InvenTree/InvenTree/tasks.py
@@ -285,7 +285,7 @@ class ScheduledTask:
     QUARTERLY: str = 'Q'
     YEARLY: str = 'Y'
 
-    TYPE: tuple[str] = (MINUTES, HOURLY, DAILY, WEEKLY, MONTHLY, QUARTERLY, YEARLY)
+    TYPE: tuple[str] = (MINUTES, HOURLY, DAILY, WEEKLY, MONTHLY, QUARTERLY, YEARLY)  # type: ignore[invalid-assignment]
 
 
 class TaskRegister:
@@ -302,7 +302,9 @@ tasks = TaskRegister()
 
 
 def scheduled_task(
-    interval: str, minutes: Optional[int] = None, tasklist: TaskRegister = None
+    interval: str,
+    minutes: Optional[int] = None,
+    tasklist: Optional[TaskRegister] = None,
 ):
     """Register the given task as a scheduled task.
 
@@ -544,7 +546,7 @@ def check_for_updates():
 
     match = re.match(r'^.*(\d+)\.(\d+)\.(\d+).*$', tag)
 
-    if len(match.groups()) != 3:  # pragma: no cover
+    if not match or len(match.groups()) != 3:  # pragma: no cover
         logger.warning("Version '%s' did not match expected pattern", tag)
         return
 
diff --git a/src/backend/InvenTree/InvenTree/test_api.py b/src/backend/InvenTree/InvenTree/test_api.py
index 1f9d91b71b..62baf46aa3 100644
--- a/src/backend/InvenTree/InvenTree/test_api.py
+++ b/src/backend/InvenTree/InvenTree/test_api.py
@@ -567,7 +567,7 @@ class GeneralApiTests(InvenTreeAPITestCase):
 
             self.assertIn('License file not found at', str(log.output))
 
-        with TemporaryDirectory() as tmp:
+        with TemporaryDirectory() as tmp:  # type: ignore[no-matching-overload]
             sample_file = Path(tmp, 'temp.txt')
             sample_file.write_text('abc')
 
diff --git a/src/backend/InvenTree/InvenTree/tracing.py b/src/backend/InvenTree/InvenTree/tracing.py
index cb91c32cbf..4cedbb584d 100644
--- a/src/backend/InvenTree/InvenTree/tracing.py
+++ b/src/backend/InvenTree/InvenTree/tracing.py
@@ -4,7 +4,7 @@ import base64
 import logging
 from typing import Optional
 
-from opentelemetry import metrics, trace
+from opentelemetry import metrics, trace  # type: ignore[import]
 from opentelemetry.instrumentation.django import DjangoInstrumentor
 from opentelemetry.instrumentation.redis import RedisInstrumentor
 from opentelemetry.instrumentation.requests import RequestsInstrumentor
@@ -29,8 +29,8 @@ TRACE_PROV = None
 
 
 def setup_tracing(
-    endpoint: str,
-    headers: dict,
+    endpoint: Optional[str] = None,
+    headers: Optional[dict] = None,
     resources_input: Optional[dict] = None,
     console: bool = False,
     auth: Optional[dict] = None,
@@ -50,6 +50,11 @@ def setup_tracing(
     """
     if InvenTree.ready.isImportingData() or InvenTree.ready.isRunningMigrations():
         return
+    if endpoint is None or headers is None:
+        print(
+            'Tracing endpoint or headers not specified - skipping tracing setup'
+        )  # pragma: no cover
+        return  # pragma: no cover
 
     # Logger configuration
     logger = logging.getLogger('inventree')
diff --git a/src/backend/InvenTree/InvenTree/unit_test.py b/src/backend/InvenTree/InvenTree/unit_test.py
index 9393d10311..b2dfacdad1 100644
--- a/src/backend/InvenTree/InvenTree/unit_test.py
+++ b/src/backend/InvenTree/InvenTree/unit_test.py
@@ -115,7 +115,7 @@ def getOldestMigrationFile(app, exclude_extension=True, ignore_initial=True):
             oldest_num = num
             oldest_file = f
 
-    if exclude_extension:
+    if exclude_extension and oldest_file:
         oldest_file = oldest_file.replace('.py', '')
 
     return oldest_file
@@ -583,6 +583,10 @@ class InvenTreeAPITestCase(
         result = re.search(
             r'(attachment|inline); filename=[\'"]([\w\d\-.]+)[\'"]', disposition
         )
+        if not result:
+            raise ValueError(
+                'No filename match found in disposition'
+            )  # pragma: no cover
 
         fn = result.groups()[1]
 
diff --git a/src/backend/InvenTree/InvenTree/validators.py b/src/backend/InvenTree/InvenTree/validators.py
index a44de39446..caf2239518 100644
--- a/src/backend/InvenTree/InvenTree/validators.py
+++ b/src/backend/InvenTree/InvenTree/validators.py
@@ -6,6 +6,7 @@ from django.core.exceptions import ValidationError
 from django.utils.translation import gettext_lazy as _
 
 import pint
+import pint.errors
 from moneyed import CURRENCIES
 
 import InvenTree.conversion
diff --git a/src/backend/InvenTree/InvenTree/version.py b/src/backend/InvenTree/InvenTree/version.py
index 0d6b2d5853..08b8bea05d 100644
--- a/src/backend/InvenTree/InvenTree/version.py
+++ b/src/backend/InvenTree/InvenTree/version.py
@@ -107,7 +107,7 @@ def inventreeVersionTuple(version=None):
 
     match = re.match(r'^.*(\d+)\.(\d+)\.(\d+).*$', str(version))
 
-    return [int(g) for g in match.groups()]
+    return [int(g) for g in match.groups()] if match else []
 
 
 def isInvenTreeDevelopmentVersion():
diff --git a/src/backend/InvenTree/build/api.py b/src/backend/InvenTree/build/api.py
index 4e110ef004..92c667e567 100644
--- a/src/backend/InvenTree/build/api.py
+++ b/src/backend/InvenTree/build/api.py
@@ -2,17 +2,21 @@
 
 from __future__ import annotations
 
+from typing import Optional
+
 from django.contrib.auth.models import User
 from django.db.models import F, Q
 from django.urls import include, path
 from django.utils.translation import gettext_lazy as _
 
 from django_filters import rest_framework as rest_filters
+from django_filters.rest_framework.filterset import FilterSet
 from drf_spectacular.utils import extend_schema, extend_schema_field
 from rest_framework import serializers, status
 from rest_framework.exceptions import ValidationError
 from rest_framework.response import Response
 
+import build.models as build_models
 import build.serializers
 import common.models
 import part.models as part_models
@@ -33,7 +37,7 @@ from InvenTree.mixins import CreateAPI, ListCreateAPI, RetrieveUpdateDestroyAPI
 from users.models import Owner
 
 
-class BuildFilter(rest_filters.FilterSet):
+class BuildFilter(FilterSet):
     """Custom filterset for BuildList API endpoint."""
 
     class Meta:
@@ -431,7 +435,7 @@ class BuildUnallocate(CreateAPI):
         return ctx
 
 
-class BuildLineFilter(rest_filters.FilterSet):
+class BuildLineFilter(FilterSet):
     """Custom filterset for the BuildLine API endpoint."""
 
     class Meta:
@@ -605,7 +609,7 @@ class BuildLineList(BuildLineMixin, DataExportViewMixin, ListCreateAPI):
         'bom_item__reference',
     ]
 
-    def get_source_build(self) -> Build | None:
+    def get_source_build(self) -> Optional[Build]:
         """Return the target build for the BuildLine queryset."""
         source_build = None
 
@@ -622,7 +626,7 @@ class BuildLineList(BuildLineMixin, DataExportViewMixin, ListCreateAPI):
 class BuildLineDetail(BuildLineMixin, RetrieveUpdateDestroyAPI):
     """API endpoint for detail view of a BuildLine object."""
 
-    def get_source_build(self) -> Build | None:
+    def get_source_build(self) -> Optional[Build]:
         """Return the target source location for the BuildLine queryset."""
         return None
 
@@ -783,7 +787,7 @@ class BuildItemDetail(RetrieveUpdateDestroyAPI):
     serializer_class = build.serializers.BuildItemSerializer
 
 
-class BuildItemFilter(rest_filters.FilterSet):
+class BuildItemFilter(FilterSet):
     """Custom filterset for the BuildItemList API endpoint."""
 
     class Meta:
@@ -829,7 +833,7 @@ class BuildItemFilter(rest_filters.FilterSet):
             return queryset.filter(stock_item__part=part)
 
     build = rest_filters.ModelChoiceFilter(
-        queryset=build.models.Build.objects.all(),
+        queryset=build_models.Build.objects.all(),
         label=_('Build Order'),
         field_name='build_line__build',
     )
diff --git a/src/backend/InvenTree/build/models.py b/src/backend/InvenTree/build/models.py
index 12817fc912..d0b223c5b2 100644
--- a/src/backend/InvenTree/build/models.py
+++ b/src/backend/InvenTree/build/models.py
@@ -1064,7 +1064,7 @@ class Build(
         lines = lines.exclude(bom_item__consumable=True)
         lines = annotate_allocated_quantity(lines)
 
-        for build_line in lines:
+        for build_line in lines:  # type: ignore[non-iterable]
             reduce_by = build_line.allocated - build_line.quantity
 
             if reduce_by <= 0:
@@ -1359,7 +1359,7 @@ class Build(
                         except (ValidationError, serializers.ValidationError) as exc:
                             # Catch model errors and re-throw as DRF errors
                             raise ValidationError(
-                                detail=serializers.as_serializer_error(exc)
+                                exc.message, detail=serializers.as_serializer_error(exc)
                             )
 
                     if unallocated_quantity <= 0:
diff --git a/src/backend/InvenTree/build/serializers.py b/src/backend/InvenTree/build/serializers.py
index f595266d7d..9361ad7ff4 100644
--- a/src/backend/InvenTree/build/serializers.py
+++ b/src/backend/InvenTree/build/serializers.py
@@ -23,6 +23,7 @@ from rest_framework.serializers import ValidationError
 
 import build.tasks
 import common.models
+import common.settings
 import company.serializers
 import InvenTree.helpers
 import InvenTree.tasks
diff --git a/src/backend/InvenTree/build/test_api.py b/src/backend/InvenTree/build/test_api.py
index d81f797693..5fd6692996 100644
--- a/src/backend/InvenTree/build/test_api.py
+++ b/src/backend/InvenTree/build/test_api.py
@@ -1,6 +1,7 @@
 """Unit tests for the BuildOrder API."""
 
 from datetime import datetime, timedelta
+from typing import Optional
 
 from django.urls import reverse
 
@@ -668,6 +669,11 @@ class BuildAllocationTest(BuildAPITest):
                 wrong_line = line
                 break
 
+        if not wrong_line:
+            raise self.fail(
+                'No matching BuildLine found for the given stock item'
+            )  # pragma: no cover
+
         data = self.post(
             self.url,
             {
@@ -695,6 +701,11 @@ class BuildAllocationTest(BuildAPITest):
                 right_line = line
                 break
 
+        if not right_line:
+            raise self.fail(
+                'No matching BuildLine found for the given stock item'
+            )  # pragma: no cover
+
         self.post(
             self.url,
             {
@@ -722,11 +733,15 @@ class BuildAllocationTest(BuildAPITest):
         # Find the correct BuildLine
         si = StockItem.objects.get(pk=2)
 
-        right_line = None
+        right_line: Optional[BuildLine] = None
         for line in self.build.build_lines.all():
             if line.bom_item.sub_part.pk == si.part.pk:
-                right_line = line
+                right_line: BuildLine = line
                 break
+        if not right_line:
+            raise self.fail(
+                'No matching BuildLine found for the given stock item'
+            )  # pragma: no cover
 
         self.post(
             self.url,
diff --git a/src/backend/InvenTree/common/api.py b/src/backend/InvenTree/common/api.py
index 1946d3a2de..e98a90e25c 100644
--- a/src/backend/InvenTree/common/api.py
+++ b/src/backend/InvenTree/common/api.py
@@ -1,6 +1,7 @@
 """Provides a JSON API for common components."""
 
 import json
+import json.decoder
 
 from django.conf import settings
 from django.contrib.contenttypes.models import ContentType
@@ -13,8 +14,9 @@ from django.utils.translation import gettext_lazy as _
 from django.views.decorators.cache import cache_control
 from django.views.decorators.csrf import csrf_exempt
 
+import django_filters.rest_framework.filters as rest_filters
 import django_q.models
-from django_filters import rest_framework as rest_filters
+from django_filters.rest_framework.filterset import FilterSet
 from django_q.tasks import async_task
 from djmoney.contrib.exchange.models import ExchangeBackend, Rate
 from drf_spectacular.utils import OpenApiResponse, extend_schema
@@ -676,7 +678,7 @@ class ContentTypeModelDetail(ContentTypeDetail):
         return super().get(request, *args, **kwargs)
 
 
-class AttachmentFilter(rest_filters.FilterSet):
+class AttachmentFilter(FilterSet):
     """Filterset for the AttachmentList API endpoint."""
 
     class Meta:
diff --git a/src/backend/InvenTree/common/currency.py b/src/backend/InvenTree/common/currency.py
index 1fed388ffe..f2fe3d76bd 100644
--- a/src/backend/InvenTree/common/currency.py
+++ b/src/backend/InvenTree/common/currency.py
@@ -160,7 +160,7 @@ def get_price(
     - If MOQ (minimum order quantity) is required, bump quantity
     - If order multiples are to be observed, then we need to calculate based on that, too
     """
-    from common.currency import currency_code_default
+    # from common.currency import currency_code_default
 
     if hasattr(instance, break_name):
         price_breaks = getattr(instance, break_name).all()
diff --git a/src/backend/InvenTree/common/models.py b/src/backend/InvenTree/common/models.py
index 8cd9751454..134163327e 100644
--- a/src/backend/InvenTree/common/models.py
+++ b/src/backend/InvenTree/common/models.py
@@ -30,6 +30,7 @@ from django.core.mail import EmailMultiAlternatives, get_connection
 from django.core.mail.utils import DNS_NAME
 from django.core.validators import MinValueValidator
 from django.db import models, transaction
+from django.db.models import enums
 from django.db.models.signals import post_delete, post_save
 from django.db.utils import IntegrityError, OperationalError, ProgrammingError
 from django.dispatch import receiver
@@ -66,7 +67,7 @@ from InvenTree.version import inventree_identifier
 logger = structlog.get_logger('inventree')
 
 
-class RenderMeta(models.enums.ChoicesMeta):
+class RenderMeta(enums.ChoicesMeta):
     """Metaclass for rendering choices."""
 
     choice_fnc = None
@@ -80,7 +81,7 @@ class RenderMeta(models.enums.ChoicesMeta):
         return []
 
 
-class RenderChoices(models.TextChoices, metaclass=RenderMeta):
+class RenderChoices(models.TextChoices, metaclass=RenderMeta):  # type: ignore
     """Class for creating enumerated string choices for schema rendering."""
 
 
@@ -971,7 +972,7 @@ class BaseInvenTreeSetting(models.Model):
 
         return setting.get('model', None)
 
-    def model_filters(self) -> dict:
+    def model_filters(self) -> Optional[dict]:
         """Return the model filters associated with this setting."""
         setting = self.get_setting_definition(
             self.key, **self.get_filters_for_instance()
@@ -1505,8 +1506,8 @@ class WebhookEndpoint(models.Model):
             request (optional): Original request object. Defaults to None.
         """
         return WebhookMessage.objects.create(
-            host=request.get_host(),
-            header=json.dumps(dict(headers.items())),
+            host=request.get_host() if request else '',
+            header=json.dumps(dict(headers.items())) if headers else None,
             body=payload,
             endpoint=self,
         )
diff --git a/src/backend/InvenTree/common/notifications.py b/src/backend/InvenTree/common/notifications.py
index 0d17f159bc..2e5ca597cb 100644
--- a/src/backend/InvenTree/common/notifications.py
+++ b/src/backend/InvenTree/common/notifications.py
@@ -84,9 +84,7 @@ class InvenTreeNotificationBodies:
     )
 
 
-def trigger_notification(
-    obj: Model, category: Optional[str] = None, obj_ref: str = 'pk', **kwargs
-):
+def trigger_notification(obj: Model, category: str = '', obj_ref: str = 'pk', **kwargs):
     """Send out a notification.
 
     Args:
diff --git a/src/backend/InvenTree/common/tests.py b/src/backend/InvenTree/common/tests.py
index 6d89322fa3..999c196a82 100644
--- a/src/backend/InvenTree/common/tests.py
+++ b/src/backend/InvenTree/common/tests.py
@@ -19,7 +19,7 @@ from django.test import Client, TestCase
 from django.test.utils import override_settings
 from django.urls import reverse
 
-import PIL
+from PIL import Image
 
 import common.validators
 from common.notifications import trigger_notification
@@ -200,7 +200,7 @@ class AttachmentTest(InvenTreeAPITestCase):
 
         # Assign 'delete' permission to 'part' model
         self.assignRole('part.delete')
-        response = self.delete(url, expected_code=204)
+        self.delete(url, expected_code=204)
 
 
 class SettingsTest(InvenTreeTestCase):
@@ -671,9 +671,9 @@ class GlobalSettingsApiTest(InvenTreeAPITestCase):
 
         # Find the associated setting
         setting = next((s for s in response.data if s['key'] == key), None)
+        assert setting is not None
 
         # Check default value (should be False, not 'False')
-        self.assertIsNotNone(setting)
         self.assertFalse(setting['value'])
 
         # Check that we can manually set the value
@@ -851,9 +851,9 @@ class UserSettingsApiTest(InvenTreeAPITestCase):
 
         # Find the associated setting
         setting = next((s for s in response.data if s['key'] == key), None)
+        assert setting is not None
 
         # Check default value (should be 10, not '10')
-        self.assertIsNotNone(setting)
         self.assertEqual(setting['value'], 10)
 
         # Check that writing an invalid value returns an error
@@ -1535,7 +1535,7 @@ class NotesImageTest(InvenTreeAPITestCase):
         n = NotesImage.objects.count()
 
         # Construct a simple image file
-        image = PIL.Image.new('RGB', (100, 100), color='red')
+        image = Image.new('RGB', (100, 100), color='red')
 
         with io.BytesIO() as output:
             image.save(output, format='PNG')
@@ -1589,6 +1589,7 @@ class ProjectCodesTest(InvenTreeAPITestCase):
 
         # Get the first project code
         code = ProjectCode.objects.first()
+        assert code is not None and code.pk
 
         # Delete it
         self.delete(
@@ -1686,6 +1687,7 @@ class CustomUnitAPITest(InvenTreeAPITestCase):
     def test_edit(self):
         """Test edit permissions for CustomUnit model."""
         unit = CustomUnit.objects.first()
+        assert unit is not None and unit.pk
 
         # Try to edit without permission
         self.user.is_staff = False
@@ -1713,6 +1715,7 @@ class CustomUnitAPITest(InvenTreeAPITestCase):
     def test_validation(self):
         """Test that validation works as expected."""
         unit = CustomUnit.objects.first()
+        assert unit is not None and unit.pk
 
         self.user.is_staff = True
         self.user.save()
diff --git a/src/backend/InvenTree/company/api.py b/src/backend/InvenTree/company/api.py
index ba103e3268..00479d69d8 100644
--- a/src/backend/InvenTree/company/api.py
+++ b/src/backend/InvenTree/company/api.py
@@ -4,7 +4,8 @@ from django.db.models import Q
 from django.urls import include, path
 from django.utils.translation import gettext_lazy as _
 
-from django_filters import rest_framework as rest_filters
+import django_filters.rest_framework.filters as rest_filters
+from django_filters.rest_framework.filterset import FilterSet
 
 import part.models
 from data_exporter.mixins import DataExportViewMixin
@@ -127,7 +128,7 @@ class AddressDetail(RetrieveUpdateDestroyAPI):
     serializer_class = AddressSerializer
 
 
-class ManufacturerPartFilter(rest_filters.FilterSet):
+class ManufacturerPartFilter(FilterSet):
     """Custom API filters for the ManufacturerPart list endpoint."""
 
     class Meta:
@@ -204,7 +205,7 @@ class ManufacturerPartDetail(RetrieveUpdateDestroyAPI):
     serializer_class = ManufacturerPartSerializer
 
 
-class ManufacturerPartParameterFilter(rest_filters.FilterSet):
+class ManufacturerPartParameterFilter(FilterSet):
     """Custom filterset for the ManufacturerPartParameterList API endpoint."""
 
     class Meta:
@@ -259,7 +260,7 @@ class ManufacturerPartParameterDetail(RetrieveUpdateDestroyAPI):
     serializer_class = ManufacturerPartParameterSerializer
 
 
-class SupplierPartFilter(rest_filters.FilterSet):
+class SupplierPartFilter(FilterSet):
     """API filters for the SupplierPartList endpoint."""
 
     class Meta:
@@ -418,7 +419,7 @@ class SupplierPartDetail(SupplierPartMixin, RetrieveUpdateDestroyAPI):
     """
 
 
-class SupplierPriceBreakFilter(rest_filters.FilterSet):
+class SupplierPriceBreakFilter(FilterSet):
     """Custom API filters for the SupplierPriceBreak list endpoint."""
 
     class Meta:
diff --git a/src/backend/InvenTree/company/migrations/0019_auto_20200413_0642.py b/src/backend/InvenTree/company/migrations/0019_auto_20200413_0642.py
index 3b7c928489..0fc852354b 100644
--- a/src/backend/InvenTree/company/migrations/0019_auto_20200413_0642.py
+++ b/src/backend/InvenTree/company/migrations/0019_auto_20200413_0642.py
@@ -51,7 +51,7 @@ def reverse_association(apps, schema_editor):  # pragma: no cover
 
         row = cursor.fetchone()
 
-        if len(row) > 0:
+        if row and len(row) > 0:
             try:
                 manufacturer_id = int(row[0])
             except (TypeError, ValueError):
@@ -67,12 +67,12 @@ def reverse_association(apps, schema_editor):  # pragma: no cover
         response = cursor.execute(f"SELECT name from company_company where id={manufacturer_id};")
 
         row = cursor.fetchone()
+        if row:
+            name = row[0]
 
-        name = row[0]
+            print(" - Manufacturer name: '{name}'".format(name=name))
 
-        print(" - Manufacturer name: '{name}'".format(name=name))
-
-        response = cursor.execute("UPDATE part_supplierpart SET manufacturer_name='{name}' WHERE id={ID};".format(name=name, ID=supplier_part_id))
+            response = cursor.execute("UPDATE part_supplierpart SET manufacturer_name='{name}' WHERE id={ID};".format(name=name, ID=supplier_part_id))
 
 def associate_manufacturers(apps, schema_editor):
     """
@@ -106,7 +106,7 @@ def associate_manufacturers(apps, schema_editor):
         response = cursor.execute(query)
         row = cursor.fetchone()
 
-        if len(row) > 0:
+        if row and len(row) > 0:
             return row[0]
         return ''  # pragma: no cover
 
@@ -296,11 +296,11 @@ def associate_manufacturers(apps, schema_editor):
 
                 # Double-check if the typed name corresponds to an existing item
                 elif response in companies.keys():
-                    link_part(part, companies[response])
+                    link_part(part_id, companies[response])
                     return
 
                 elif response in links.keys():
-                    link_part(part, links[response])
+                    link_part(part_id, links[response])
                     return
 
                 # No match, create a new manufacturer
diff --git a/src/backend/InvenTree/company/test_api.py b/src/backend/InvenTree/company/test_api.py
index 27ac623bbe..4383b77583 100644
--- a/src/backend/InvenTree/company/test_api.py
+++ b/src/backend/InvenTree/company/test_api.py
@@ -156,7 +156,10 @@ class CompanyTest(InvenTreeAPITestCase):
 
     def test_company_notes(self):
         """Test the markdown 'notes' field for the Company model."""
-        pk = Company.objects.first().pk
+        company = Company.objects.first()
+        assert company
+        pk = company.pk
+
         url = reverse('api-company-detail', kwargs={'pk': pk})
 
         # Attempt to inject malicious markdown into the "notes" field
@@ -253,6 +256,7 @@ class ContactTest(InvenTreeAPITestCase):
         n = Contact.objects.count()
 
         company = Company.objects.first()
+        assert company
 
         # Without required permissions, creation should fail
         self.post(
@@ -271,6 +275,8 @@ class ContactTest(InvenTreeAPITestCase):
         """Test that we can edit a Contact via the API."""
         # Get the first contact
         contact = Contact.objects.first()
+        assert contact
+
         # Use this contact in the tests
         url = reverse('api-contact-detail', kwargs={'pk': contact.pk})
 
@@ -294,6 +300,8 @@ class ContactTest(InvenTreeAPITestCase):
         """Tests that we can delete a Contact via the API."""
         # Get the last contact
         contact = Contact.objects.first()
+        assert contact
+
         url = reverse('api-contact-detail', kwargs={'pk': contact.pk})
 
         # Delete (without required permissions)
@@ -348,6 +356,7 @@ class AddressTest(InvenTreeAPITestCase):
     def test_filter_list(self):
         """Test listing addresses filtered on company."""
         company = Company.objects.first()
+        assert company
 
         response = self.get(self.url, {'company': company.pk}, expected_code=200)
 
@@ -356,6 +365,7 @@ class AddressTest(InvenTreeAPITestCase):
     def test_create(self):
         """Test creating a new address."""
         company = Company.objects.first()
+        assert company
 
         self.post(self.url, {'company': company.pk, 'title': 'HQ'}, expected_code=403)
 
@@ -366,6 +376,7 @@ class AddressTest(InvenTreeAPITestCase):
     def test_get(self):
         """Test that objects are properly returned from a get."""
         addr = Address.objects.first()
+        assert addr
 
         url = reverse('api-address-detail', kwargs={'pk': addr.pk})
         response = self.get(url, expected_code=200)
@@ -386,6 +397,7 @@ class AddressTest(InvenTreeAPITestCase):
     def test_edit(self):
         """Test editing an Address object."""
         addr = Address.objects.first()
+        assert addr
 
         url = reverse('api-address-detail', kwargs={'pk': addr.pk})
 
@@ -403,6 +415,7 @@ class AddressTest(InvenTreeAPITestCase):
     def test_delete(self):
         """Test deleting an object."""
         addr = Address.objects.first()
+        assert addr
 
         url = reverse('api-address-detail', kwargs={'pk': addr.pk})
 
diff --git a/src/backend/InvenTree/data_exporter/apps.py b/src/backend/InvenTree/data_exporter/apps.py
index a9eb5d8bbd..9cef065b15 100644
--- a/src/backend/InvenTree/data_exporter/apps.py
+++ b/src/backend/InvenTree/data_exporter/apps.py
@@ -18,7 +18,7 @@ class DataExporterConfig(AppConfig):
     def cleanup(self):
         """Cleanup any old export files."""
         try:
-            from data_exporter.tasks import cleanup_old_export_outputs
+            from data_exporter.tasks import cleanup_old_export_outputs  # type: ignore
 
             cleanup_old_export_outputs()
         except Exception:
diff --git a/src/backend/InvenTree/data_exporter/mixins.py b/src/backend/InvenTree/data_exporter/mixins.py
index 404c686056..33077354ff 100644
--- a/src/backend/InvenTree/data_exporter/mixins.py
+++ b/src/backend/InvenTree/data_exporter/mixins.py
@@ -1,6 +1,7 @@
 """Mixin classes for the exporter app."""
 
 from collections import OrderedDict
+from typing import Any
 
 from django.core.exceptions import ValidationError
 from django.core.files.base import ContentFile
@@ -127,7 +128,7 @@ class DataExportSerializerMixin:
         """
         return headers
 
-    def get_nested_value(self, row: dict, key: str) -> any:
+    def get_nested_value(self, row: dict, key: str) -> Any:
         """Get a nested value from a dictionary.
 
         This method allows for dot notation to access nested fields.
diff --git a/src/backend/InvenTree/data_exporter/serializers.py b/src/backend/InvenTree/data_exporter/serializers.py
index 2039b79521..de535a74a1 100644
--- a/src/backend/InvenTree/data_exporter/serializers.py
+++ b/src/backend/InvenTree/data_exporter/serializers.py
@@ -6,7 +6,6 @@ from rest_framework import serializers
 
 import InvenTree.exceptions
 import InvenTree.helpers
-import InvenTree.serializers
 from plugin import PluginMixinEnum, registry
 
 
@@ -53,7 +52,7 @@ class DataExportOptionsSerializer(serializers.Serializer):
             try:
                 supports_export = plugin.supports_export(
                     model_class,
-                    user=request.user,
+                    user=request.user if request else None,
                     serializer_class=serializer_class,
                     view_class=view_class,
                 )
diff --git a/src/backend/InvenTree/generic/states/__init__.py b/src/backend/InvenTree/generic/states/__init__.py
index 35e997fbeb..f0eb63ba64 100644
--- a/src/backend/InvenTree/generic/states/__init__.py
+++ b/src/backend/InvenTree/generic/states/__init__.py
@@ -6,6 +6,7 @@ There is a rendered state for each state value. The rendered state is used for d
 States can be extended with custom options for each InvenTree instance - those options are stored in the database and need to link back to state values.
 """
 
+from . import fields
 from .states import ColorEnum, StatusCode, StatusCodeMixin
 from .transition import StateTransitionMixin, TransitionMethod
 
@@ -15,4 +16,5 @@ __all__ = [
     'StatusCode',
     'StatusCodeMixin',
     'TransitionMethod',
+    'fields',
 ]
diff --git a/src/backend/InvenTree/generic/states/states.py b/src/backend/InvenTree/generic/states/states.py
index e66971f393..3984947888 100644
--- a/src/backend/InvenTree/generic/states/states.py
+++ b/src/backend/InvenTree/generic/states/states.py
@@ -4,6 +4,7 @@ import enum
 import logging
 import re
 from enum import Enum
+from typing import Optional
 
 logger = logging.getLogger('inventree')
 
@@ -297,7 +298,7 @@ class StatusCodeMixin:
         """Return the status code for this object."""
         return getattr(self, self.STATUS_FIELD)
 
-    def get_custom_status(self) -> int:
+    def get_custom_status(self) -> Optional[int]:
         """Return the custom status code for this object."""
         return getattr(self, f'{self.STATUS_FIELD}_custom_key', None)
 
diff --git a/src/backend/InvenTree/generic/states/tags.py b/src/backend/InvenTree/generic/states/tags.py
index f93a6b8a96..1424fea033 100644
--- a/src/backend/InvenTree/generic/states/tags.py
+++ b/src/backend/InvenTree/generic/states/tags.py
@@ -20,4 +20,5 @@ def status_label(typ: str, key: int, include_custom: bool = False, *args, **kwar
 def display_status_label(typ: str, key: int, fallback: int, *args, **kwargs):
     """Render a status label."""
     render_key = int(key) if key else fallback
-    return status_label(typ, render_key, *args, include_custom=True, **kwargs)
+    kwargs['include_custom'] = True
+    return status_label(typ, render_key, *args, **kwargs)
diff --git a/src/backend/InvenTree/generic/states/transition.py b/src/backend/InvenTree/generic/states/transition.py
index 0c4c6e9089..f8d049c6ec 100644
--- a/src/backend/InvenTree/generic/states/transition.py
+++ b/src/backend/InvenTree/generic/states/transition.py
@@ -1,5 +1,7 @@
 """Classes and functions for plugin controlled object state transitions."""
 
+from typing import Callable
+
 from django.db.models import Model
 
 import structlog
@@ -30,7 +32,7 @@ class TransitionMethod:
         current_state: int,
         target_state: int,
         instance: Model,
-        default_action: callable,
+        default_action: Callable,
         **kwargs,
     ) -> bool:
         """Perform a state transition.
diff --git a/src/backend/InvenTree/importer/models.py b/src/backend/InvenTree/importer/models.py
index 468fe11542..6a887785bd 100644
--- a/src/backend/InvenTree/importer/models.py
+++ b/src/backend/InvenTree/importer/models.py
@@ -303,9 +303,7 @@ class DataImportSession(models.Model):
             if not any(row_data.values()):
                 continue
 
-            row = importer.models.DataImportRow(
-                session=self, row_data=row_data, row_index=idx
-            )
+            row = DataImportRow(session=self, row_data=row_data, row_index=idx)
 
             row.extract_data(
                 field_mapping=field_mapping,
@@ -317,7 +315,7 @@ class DataImportSession(models.Model):
             imported_rows.append(row)
 
         # Perform database writes as a single operation
-        importer.models.DataImportRow.objects.bulk_create(imported_rows)
+        DataImportRow.objects.bulk_create(imported_rows)
 
         # Mark the import task as "PROCESSING"
         self.status = DataImportStatusCode.PROCESSING.value
diff --git a/src/backend/InvenTree/importer/operations.py b/src/backend/InvenTree/importer/operations.py
index dcb79e8baa..0efca9017c 100644
--- a/src/backend/InvenTree/importer/operations.py
+++ b/src/backend/InvenTree/importer/operations.py
@@ -1,9 +1,12 @@
 """Data import operational functions."""
 
+from typing import Optional
+
 from django.core.exceptions import ValidationError
 from django.utils.translation import gettext_lazy as _
 
 import tablib
+import tablib.core
 
 import InvenTree.helpers
 
@@ -82,7 +85,7 @@ def extract_column_names(data_file) -> list:
     return headers
 
 
-def get_field_label(field) -> str:
+def get_field_label(field) -> Optional[str]:
     """Return the label for a field in a serializer class.
 
     Check for labels in the following order of descending priority:
diff --git a/src/backend/InvenTree/machine/models.py b/src/backend/InvenTree/machine/models.py
index e22d32741b..fd8c62df34 100755
--- a/src/backend/InvenTree/machine/models.py
+++ b/src/backend/InvenTree/machine/models.py
@@ -1,7 +1,7 @@
 """Models for the machine app."""
 
 import uuid
-from typing import Literal
+from typing import Literal, Optional
 
 from django.contrib import admin
 from django.db import models
@@ -192,7 +192,7 @@ class MachineSetting(common.models.BaseInvenTreeSetting):
         If not provided, we'll look at the machine registry to see what settings this machine driver requires
         """
         if 'settings' not in kwargs:
-            machine_config: MachineConfig = kwargs.pop('machine_config', None)
+            machine_config: Optional[MachineConfig] = kwargs.pop('machine_config', None)
             if machine_config and machine_config.machine:
                 config_type = kwargs.get('config_type')
                 if config_type == cls.ConfigType.DRIVER:
diff --git a/src/backend/InvenTree/machine/registry.py b/src/backend/InvenTree/machine/registry.py
index 7121b3c388..a509384a87 100644
--- a/src/backend/InvenTree/machine/registry.py
+++ b/src/backend/InvenTree/machine/registry.py
@@ -423,7 +423,9 @@ class MachineRegistry(
 
         # If the plugin registry has changed, the machine registry hash will change
         plugin_registry.update_plugin_hash()
-        data.update(plugin_registry.registry_hash.encode())
+        current_hash = plugin_registry.registry_hash
+        if current_hash:
+            data.update(current_hash.encode())
 
         for pk, machine in self.machines.items():
             data.update(str(pk).encode())
diff --git a/src/backend/InvenTree/machine/tests.py b/src/backend/InvenTree/machine/tests.py
index cedef45648..e53cb2b7e1 100755
--- a/src/backend/InvenTree/machine/tests.py
+++ b/src/backend/InvenTree/machine/tests.py
@@ -220,6 +220,7 @@ class TestLabelPrinterMachineType(InvenTreeAPITestCase):
 
         parts = Part.objects.all()[:2]
         template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()
+        assert template
 
         url = reverse('api-label-print')
 
diff --git a/src/backend/InvenTree/order/api.py b/src/backend/InvenTree/order/api.py
index 31205352e1..078e7b739d 100644
--- a/src/backend/InvenTree/order/api.py
+++ b/src/backend/InvenTree/order/api.py
@@ -11,8 +11,9 @@ from django.http.response import JsonResponse
 from django.urls import include, path, re_path
 from django.utils.translation import gettext_lazy as _
 
+import django_filters.rest_framework.filters as rest_filters
 import rest_framework.serializers
-from django_filters import rest_framework as rest_filters
+from django_filters.rest_framework.filterset import FilterSet
 from django_ical.views import ICalFeed
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import extend_schema, extend_schema_field
@@ -100,7 +101,7 @@ class OrderCreateMixin:
         )
 
 
-class OrderFilter(rest_filters.FilterSet):
+class OrderFilter(FilterSet):
     """Base class for custom API filters for the OrderList endpoint."""
 
     # Filter against order status
@@ -258,7 +259,7 @@ class OrderFilter(rest_filters.FilterSet):
         return queryset.filter(q1 | q2 | q3 | q4).distinct()
 
 
-class LineItemFilter(rest_filters.FilterSet):
+class LineItemFilter(FilterSet):
     """Base class for custom API filters for order line item list(s)."""
 
     # Filter by order status
@@ -1147,7 +1148,7 @@ class SalesOrderAllocate(SalesOrderContextMixin, CreateAPI):
     serializer_class = serializers.SalesOrderShipmentAllocationSerializer
 
 
-class SalesOrderAllocationFilter(rest_filters.FilterSet):
+class SalesOrderAllocationFilter(FilterSet):
     """Custom filterset for the SalesOrderAllocationList endpoint."""
 
     class Meta:
@@ -1321,7 +1322,7 @@ class SalesOrderAllocationDetail(SalesOrderAllocationMixin, RetrieveUpdateDestro
     """API endpoint for detali view of a SalesOrderAllocation object."""
 
 
-class SalesOrderShipmentFilter(rest_filters.FilterSet):
+class SalesOrderShipmentFilter(FilterSet):
     """Custom filterset for the SalesOrderShipmentList endpoint."""
 
     class Meta:
diff --git a/src/backend/InvenTree/order/tasks.py b/src/backend/InvenTree/order/tasks.py
index 7d2b3845eb..b44f117d39 100644
--- a/src/backend/InvenTree/order/tasks.py
+++ b/src/backend/InvenTree/order/tasks.py
@@ -1,6 +1,7 @@
 """Background tasks for the 'order' app."""
 
 from datetime import datetime, timedelta
+from typing import Union
 
 from django.contrib.auth.models import Group, User
 from django.db import transaction
@@ -104,7 +105,7 @@ def check_overdue_purchase_orders():
 @tracer.start_as_current_span('notify_overdue_sales_order')
 def notify_overdue_sales_order(so: order.models.SalesOrder) -> None:
     """Notify appropriate users that a SalesOrder has just become 'overdue'."""
-    targets: list[User, Group, Owner] = []
+    targets: list[Union[User, Group, Owner]] = []
 
     if so.created_by:
         targets.append(so.created_by)
@@ -171,7 +172,7 @@ def check_overdue_sales_orders():
 @tracer.start_as_current_span('notify_overdue_return_order')
 def notify_overdue_return_order(ro: order.models.ReturnOrder) -> None:
     """Notify appropriate users that a ReturnOrder has just become 'overdue'."""
-    targets: list[User, Group, Owner] = []
+    targets: list[Union[User, Group, Owner]] = []
 
     if ro.created_by:
         targets.append(ro.created_by)
diff --git a/src/backend/InvenTree/order/test_api.py b/src/backend/InvenTree/order/test_api.py
index d9d35090ef..31d2bdde67 100644
--- a/src/backend/InvenTree/order/test_api.py
+++ b/src/backend/InvenTree/order/test_api.py
@@ -4,6 +4,7 @@ import base64
 import io
 import json
 from datetime import date, datetime, timedelta
+from typing import Optional
 
 from django.core.exceptions import ValidationError
 from django.db import connection
@@ -420,7 +421,9 @@ class PurchaseOrderTest(OrderTest):
 
         self.assertIn('Responsible user or group must be specified', str(response.data))
 
-        data['responsible'] = Owner.objects.first().pk
+        owner = Owner.objects.first()
+        assert owner
+        data['responsible'] = owner.pk
 
         response = self.post(url, data, expected_code=201)
 
@@ -1689,6 +1692,7 @@ class SalesOrderTest(OrderTest):
             shipment = models.SalesOrderShipment.objects.create(
                 order=so, reference='SHIP-12345'
             )
+        assert shipment
 
         # Allocate some stock
         item = StockItem.objects.create(part=part, quantity=100, location=None)
@@ -1825,10 +1829,13 @@ class SalesOrderLineItemTest(OrderTest):
         self.assignRole('sales_order.add')
 
         # Crete a new SalesOrder via the API
+        company = Company.objects.filter(is_customer=True).first()
+        assert company
+
         response = self.post(
             reverse('api-so-list'),
             {
-                'customer': Company.objects.filter(is_customer=True).first().pk,
+                'customer': company.pk,
                 'reference': 'SO-12345',
                 'description': 'Test Sales Order',
             },
@@ -1878,6 +1885,7 @@ class SalesOrderLineItemTest(OrderTest):
             p = Part.objects.get(pk=item)
             s = StockItem.objects.create(part=p, quantity=100)
             l = models.SalesOrderLineItem.objects.filter(order=order, part=p).first()
+            assert l
 
             # Allocate against the API
             self.post(
@@ -2099,12 +2107,14 @@ class SalesOrderAllocateTest(OrderTest):
             return line_item.part.is_template
 
         for line in filter(check_template, self.order.lines.all()):
-            stock_item = None
+            stock_item: Optional[StockItem] = None
 
             stock_item = None
 
             # Allocate a matching variant
-            parts = Part.objects.filter(salable=True).filter(variant_of=line.part.pk)
+            parts: list[Part] = Part.objects.filter(salable=True).filter(
+                variant_of=line.part.pk
+            )
             for part in parts:
                 stock_item = part.stock_items.last()
 
@@ -2118,6 +2128,9 @@ class SalesOrderAllocateTest(OrderTest):
                 if stock_item is not None:
                     break
 
+            if stock_item is None:
+                raise self.fail('No stock item found for part')  # pragma: no cover
+
             # Fully-allocate each line
             data['items'].append({
                 'line_item': line.pk,
diff --git a/src/backend/InvenTree/part/api.py b/src/backend/InvenTree/part/api.py
index 94a1dd6c65..ab3cf63d0c 100644
--- a/src/backend/InvenTree/part/api.py
+++ b/src/backend/InvenTree/part/api.py
@@ -6,8 +6,9 @@ from django.db.models import Count, F, Q
 from django.urls import include, path
 from django.utils.translation import gettext_lazy as _
 
-from django_filters import rest_framework as rest_filters
+import django_filters.rest_framework.filters as rest_filters
 from django_filters.rest_framework import DjangoFilterBackend
+from django_filters.rest_framework.filterset import FilterSet
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import extend_schema_field
 from rest_framework import serializers
@@ -98,7 +99,7 @@ class CategoryMixin:
         return ctx
 
 
-class CategoryFilter(rest_filters.FilterSet):
+class CategoryFilter(FilterSet):
     """Custom filterset class for the PartCategoryList endpoint."""
 
     class Meta:
@@ -282,11 +283,11 @@ class CategoryDetail(CategoryMixin, CustomRetrieveUpdateDestroyAPI):
         return super().destroy(
             request,
             *args,
-            **dict(
-                kwargs,
-                delete_parts=delete_parts,
-                delete_child_categories=delete_child_categories,
-            ),
+            **{
+                **kwargs,
+                'delete_parts': delete_parts,
+                'delete_child_categories': delete_child_categories,
+            },
         )
 
 
@@ -399,7 +400,7 @@ class PartInternalPriceList(DataExportViewMixin, ListCreateAPI):
     ordering = 'quantity'
 
 
-class PartTestTemplateFilter(rest_filters.FilterSet):
+class PartTestTemplateFilter(FilterSet):
     """Custom filterset class for the PartTestTemplateList endpoint."""
 
     class Meta:
@@ -644,7 +645,7 @@ class PartValidateBOM(RetrieveUpdateAPI):
         return Response(serializer.data)
 
 
-class PartFilter(rest_filters.FilterSet):
+class PartFilter(FilterSet):
     """Custom filters for the PartList endpoint.
 
     Uses the django_filters extension framework
@@ -1196,7 +1197,7 @@ class PartDetail(PartMixin, RetrieveUpdateDestroyAPI):
         return response
 
 
-class PartRelatedFilter(rest_filters.FilterSet):
+class PartRelatedFilter(FilterSet):
     """FilterSet for PartRelated objects."""
 
     class Meta:
@@ -1243,7 +1244,7 @@ class PartRelatedDetail(PartRelatedMixin, RetrieveUpdateDestroyAPI):
     """API endpoint for accessing detail view of a PartRelated object."""
 
 
-class PartParameterTemplateFilter(rest_filters.FilterSet):
+class PartParameterTemplateFilter(FilterSet):
     """FilterSet for PartParameterTemplate objects."""
 
     class Meta:
@@ -1377,7 +1378,7 @@ class PartParameterAPIMixin:
         return super().get_serializer(*args, **kwargs)
 
 
-class PartParameterFilter(rest_filters.FilterSet):
+class PartParameterFilter(FilterSet):
     """Custom filters for the PartParameterList API endpoint."""
 
     class Meta:
@@ -1438,7 +1439,7 @@ class PartParameterDetail(PartParameterAPIMixin, RetrieveUpdateDestroyAPI):
     """API endpoint for detail view of a single PartParameter object."""
 
 
-class PartStocktakeFilter(rest_filters.FilterSet):
+class PartStocktakeFilter(FilterSet):
     """Custom filter for the PartStocktakeList endpoint."""
 
     class Meta:
@@ -1480,7 +1481,7 @@ class PartStocktakeDetail(RetrieveUpdateDestroyAPI):
     serializer_class = part_serializers.PartStocktakeSerializer
 
 
-class BomFilter(rest_filters.FilterSet):
+class BomFilter(FilterSet):
     """Custom filters for the BOM list."""
 
     class Meta:
diff --git a/src/backend/InvenTree/part/filters.py b/src/backend/InvenTree/part/filters.py
index a7482036dc..33f3998ab6 100644
--- a/src/backend/InvenTree/part/filters.py
+++ b/src/backend/InvenTree/part/filters.py
@@ -12,6 +12,7 @@ Useful References:
 """
 
 from decimal import Decimal
+from typing import Optional
 
 from django.db import models
 from django.db.models import (
@@ -137,7 +138,7 @@ def annotate_on_order_quantity(reference: str = '') -> QuerySet:
     )
 
 
-def annotate_total_stock(reference: str = '', filter: Q = None) -> QuerySet:
+def annotate_total_stock(reference: str = '', filter: Optional[Q] = None) -> QuerySet:
     """Annotate 'total stock' quantity against a queryset.
 
     - This function calculates the 'total stock' for a given part
@@ -269,7 +270,7 @@ def annotate_sales_order_allocations(reference: str = '', location=None) -> Quer
     )
 
 
-def variant_stock_query(reference: str = '', filter: Q = None) -> QuerySet:
+def variant_stock_query(reference: str = '', filter: Optional[Q] = None) -> QuerySet:
     """Create a queryset to retrieve all stock items for variant parts under the specified part.
 
     - Useful for annotating a queryset with aggregated information about variant parts
diff --git a/src/backend/InvenTree/part/models.py b/src/backend/InvenTree/part/models.py
index 446f12d743..64ce7eedd0 100644
--- a/src/backend/InvenTree/part/models.py
+++ b/src/backend/InvenTree/part/models.py
@@ -819,7 +819,7 @@ class Part(
         if not check_duplicates:
             return
 
-        from part.models import Part
+        # from part.models import Part
         from stock.models import StockItem
 
         if get_global_setting('SERIAL_NUMBER_GLOBALLY_UNIQUE', False):
@@ -850,7 +850,7 @@ class Part(
 
     def find_conflicting_serial_numbers(self, serials: list) -> list:
         """For a provided list of serials, return a list of those which are conflicting."""
-        from part.models import Part
+        # from part.models import Part
         from stock.models import StockItem
 
         conflicts = []
diff --git a/src/backend/InvenTree/part/test_api.py b/src/backend/InvenTree/part/test_api.py
index 2eb9c704ae..523dbba615 100644
--- a/src/backend/InvenTree/part/test_api.py
+++ b/src/backend/InvenTree/part/test_api.py
@@ -11,7 +11,7 @@ from django.db import connection
 from django.test.utils import CaptureQueriesContext
 from django.urls import reverse
 
-import PIL
+from PIL import Image
 from rest_framework.test import APIClient
 
 import build.models
@@ -65,7 +65,7 @@ class PartImageTestMixin:
 
         fn = get_testfolder_dir() / 'part_image_123abc.png'
 
-        img = PIL.Image.new('RGB', (128, 128), color='blue')
+        img = Image.new('RGB', (128, 128), color='blue')
         img.save(fn)
 
         with open(fn, 'rb') as img_file:
@@ -1770,7 +1770,7 @@ class PartDetailTests(PartImageTestMixin, PartAPITestBase):
         for fmt in ['jpg', 'j2k', 'png', 'bmp', 'webp']:
             fn = f'{test_path}.{fmt}'
 
-            img = PIL.Image.new('RGB', (128, 128), color='red')
+            img = Image.new('RGB', (128, 128), color='red')
             img.save(fn)
 
             with open(fn, 'rb') as dummy_image:
@@ -1820,7 +1820,7 @@ class PartDetailTests(PartImageTestMixin, PartAPITestBase):
 
         fn = get_testfolder_dir() / 'part_image_123abc.png'
 
-        img = PIL.Image.new('RGB', (128, 128), color='blue')
+        img = Image.new('RGB', (128, 128), color='blue')
         img.save(fn)
 
         # Upload the image to a part
@@ -2463,6 +2463,7 @@ class BomItemTest(InvenTreeAPITestCase):
 
         # Now, let's validate an item
         bom_item = BomItem.objects.first()
+        assert bom_item
 
         bom_item.validate_hash()
 
@@ -3109,6 +3110,7 @@ class PartTestTemplateTest(PartAPITestBase):
     def test_choices(self):
         """Test the 'choices' field for the PartTestTemplate model."""
         template = PartTestTemplate.objects.first()
+        assert template
 
         url = reverse('api-part-test-template-detail', kwargs={'pk': template.pk})
 
diff --git a/src/backend/InvenTree/plugin/admin.py b/src/backend/InvenTree/plugin/admin.py
index a1643bc405..d764841607 100644
--- a/src/backend/InvenTree/plugin/admin.py
+++ b/src/backend/InvenTree/plugin/admin.py
@@ -2,8 +2,8 @@
 
 from django.contrib import admin
 
-import plugin.registry as pl_registry
 from plugin import models
+from plugin.registry import registry as pl_registry
 
 
 def plugin_update(queryset, new_status: bool):
diff --git a/src/backend/InvenTree/plugin/api.py b/src/backend/InvenTree/plugin/api.py
index f5c4c8acaa..3e62ff606f 100644
--- a/src/backend/InvenTree/plugin/api.py
+++ b/src/backend/InvenTree/plugin/api.py
@@ -6,8 +6,9 @@ from django.core.exceptions import ValidationError
 from django.urls import include, path, re_path
 from django.utils.translation import gettext_lazy as _
 
-from django_filters import rest_framework as rest_filters
+import django_filters.rest_framework.filters as rest_filters
 from django_filters.rest_framework import DjangoFilterBackend
+from django_filters.rest_framework.filterset import FilterSet
 from drf_spectacular.utils import extend_schema
 from rest_framework import status
 from rest_framework.exceptions import NotFound
@@ -36,7 +37,7 @@ from plugin.plugin import InvenTreePlugin
 from plugin.registry import registry
 
 
-class PluginFilter(rest_filters.FilterSet):
+class PluginFilter(FilterSet):
     """Filter for the PluginConfig model.
 
     Provides custom filtering options for the FilterList API endpoint.
diff --git a/src/backend/InvenTree/plugin/base/barcodes/api.py b/src/backend/InvenTree/plugin/base/barcodes/api.py
index fdbc6437b8..06640bc453 100644
--- a/src/backend/InvenTree/plugin/base/barcodes/api.py
+++ b/src/backend/InvenTree/plugin/base/barcodes/api.py
@@ -5,7 +5,7 @@ from django.urls import include, path
 from django.utils.translation import gettext_lazy as _
 
 import structlog
-from django_filters import rest_framework as rest_filters
+from django_filters.rest_framework.filterset import FilterSet
 from drf_spectacular.utils import extend_schema, extend_schema_view
 from rest_framework import status
 from rest_framework.exceptions import PermissionDenied, ValidationError
@@ -770,7 +770,7 @@ class BarcodeScanResultMixin:
         return queryset
 
 
-class BarcodeScanResultFilter(rest_filters.FilterSet):
+class BarcodeScanResultFilter(FilterSet):
     """Custom filterset for the BarcodeScanResult API."""
 
     class Meta:
diff --git a/src/backend/InvenTree/plugin/base/barcodes/mixins.py b/src/backend/InvenTree/plugin/base/barcodes/mixins.py
index 413c5f8d7b..828f015fd6 100644
--- a/src/backend/InvenTree/plugin/base/barcodes/mixins.py
+++ b/src/backend/InvenTree/plugin/base/barcodes/mixins.py
@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+from typing import Optional
+
 from django.core.exceptions import ValidationError
 from django.db.models import Q
 from django.utils.translation import gettext_lazy as _
@@ -113,7 +115,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
 
         return fields.get(key, backup_value)
 
-    def get_part(self) -> Part | None:
+    def get_part(self) -> Optional[Part]:
         """Extract the Part object from the barcode fields."""
         # TODO: Implement this
         return None
@@ -128,7 +130,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
         """Return the supplier part number from the barcode fields."""
         return self.get_field_value(self.SUPPLIER_PART_NUMBER)
 
-    def get_supplier_part(self) -> SupplierPart | None:
+    def get_supplier_part(self) -> Optional[SupplierPart]:
         """Return the SupplierPart object for the scanned barcode.
 
         Returns:
@@ -172,7 +174,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
         """Return the manufacturer part number from the barcode fields."""
         return self.get_field_value(self.MANUFACTURER_PART_NUMBER)
 
-    def get_manufacturer_part(self) -> ManufacturerPart | None:
+    def get_manufacturer_part(self) -> Optional[ManufacturerPart]:
         """Return the ManufacturerPart object for the scanned barcode.
 
         Returns:
@@ -213,7 +215,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
         """Return the supplier order number from the barcode fields."""
         return self.get_field_value(self.SUPPLIER_ORDER_NUMBER)
 
-    def get_purchase_order(self) -> PurchaseOrder | None:
+    def get_purchase_order(self) -> Optional[PurchaseOrder]:
         """Extract the PurchaseOrder object from the barcode fields.
 
         Inspect the customer_order_number and supplier_order_number fields,
@@ -260,7 +262,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
             'extract_barcode_fields must be implemented by each plugin'
         )
 
-    def scan(self, barcode_data: str) -> dict:
+    def scan(self, barcode_data: str) -> Optional[dict]:
         """Perform a generic 'scan' operation on a supplier barcode.
 
         The supplier barcode may provide sufficient information to match against
@@ -319,7 +321,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
         location=None,
         auto_allocate: bool = True,
         **kwargs,
-    ) -> dict | None:
+    ) -> Optional[dict]:
         """Attempt to receive an item against a PurchaseOrder via barcode scanning.
 
         Arguments:
@@ -430,7 +432,7 @@ class SupplierBarcodeMixin(BarcodeMixin):
 
         return response
 
-    def get_supplier(self, cache: bool = False) -> Company | None:
+    def get_supplier(self, cache: bool = False) -> Optional[Company]:
         """Get the supplier for the SUPPLIER_ID set in the plugin settings.
 
         If it's not defined, try to guess it and set it if possible.
@@ -461,9 +463,12 @@ class SupplierBarcodeMixin(BarcodeMixin):
         if len(suppliers) != 1:
             return _cache_supplier(None)
 
-        self.set_setting('SUPPLIER_ID', suppliers.first().pk)
+        supplier = suppliers.first()
+        assert supplier
 
-        return _cache_supplier(suppliers.first())
+        self.set_setting('SUPPLIER_ID', supplier.pk)
+
+        return _cache_supplier(supplier)
 
     @classmethod
     def ecia_field_map(cls):
diff --git a/src/backend/InvenTree/plugin/base/integration/APICallMixin.py b/src/backend/InvenTree/plugin/base/integration/APICallMixin.py
index d67bc64857..85cd21825f 100644
--- a/src/backend/InvenTree/plugin/base/integration/APICallMixin.py
+++ b/src/backend/InvenTree/plugin/base/integration/APICallMixin.py
@@ -163,7 +163,8 @@ class APICallMixin:
             url = f'{self.api_url}/{endpoint}'
 
         # build kwargs for call
-        kwargs.update({'url': url, 'headers': headers})
+        kwargs.update({'headers': headers})
+        kwargs.pop('url', None)
 
         if data and json:
             raise ValueError('You can either pass `data` or `json` to this function.')
@@ -175,7 +176,7 @@ class APICallMixin:
             kwargs['data'] = data
 
         # run command
-        response = requests.request(method, **kwargs)
+        response = requests.request(method, url=url, **kwargs)
 
         # return
         if simple_response:
diff --git a/src/backend/InvenTree/plugin/base/integration/DataExport.py b/src/backend/InvenTree/plugin/base/integration/DataExport.py
index 6d1eadb6e1..603f5d234d 100644
--- a/src/backend/InvenTree/plugin/base/integration/DataExport.py
+++ b/src/backend/InvenTree/plugin/base/integration/DataExport.py
@@ -1,7 +1,7 @@
 """Plugin class for custom data exporting."""
 
 from collections import OrderedDict
-from typing import Union
+from typing import Optional, Union
 
 from django.contrib.auth.models import User
 from django.db.models import QuerySet
@@ -36,8 +36,8 @@ class DataExportMixin:
         self,
         model_class: type,
         user: User,
-        serializer_class: serializers.Serializer = None,
-        view_class: views.APIView = None,
+        serializer_class: Optional[serializers.Serializer] = None,
+        view_class: Optional[views.APIView] = None,
         *args,
         **kwargs,
     ) -> bool:
diff --git a/src/backend/InvenTree/plugin/base/integration/ValidationMixin.py b/src/backend/InvenTree/plugin/base/integration/ValidationMixin.py
index 341696bf62..0678bb3260 100644
--- a/src/backend/InvenTree/plugin/base/integration/ValidationMixin.py
+++ b/src/backend/InvenTree/plugin/base/integration/ValidationMixin.py
@@ -72,7 +72,7 @@ class ValidationMixin:
 
     def validate_model_instance(
         self, instance: Model, deltas: Optional[dict] = None
-    ) -> None:
+    ) -> Optional[bool]:
         """Run custom validation on a database model instance.
 
         This method is called when a model instance is being validated.
@@ -90,7 +90,7 @@ class ValidationMixin:
         """
         return None
 
-    def validate_part_name(self, name: str, part: part.models.Part) -> None:
+    def validate_part_name(self, name: str, part: part.models.Part) -> Optional[bool]:
         """Perform validation on a proposed Part name.
 
         Arguments:
@@ -105,7 +105,7 @@ class ValidationMixin:
         """
         return None
 
-    def validate_part_ipn(self, ipn: str, part: part.models.Part) -> None:
+    def validate_part_ipn(self, ipn: str, part: part.models.Part) -> Optional[bool]:
         """Perform validation on a proposed Part IPN (internal part number).
 
         Arguments:
@@ -122,7 +122,7 @@ class ValidationMixin:
 
     def validate_batch_code(
         self, batch_code: str, item: stock.models.StockItem
-    ) -> None:
+    ) -> Optional[bool]:
         """Validate the supplied batch code.
 
         Arguments:
@@ -137,7 +137,7 @@ class ValidationMixin:
         """
         return None
 
-    def generate_batch_code(self, **kwargs) -> str:
+    def generate_batch_code(self, **kwargs) -> Optional[str]:
         """Generate a new batch code.
 
         This method is called when a new batch code is required.
@@ -154,8 +154,8 @@ class ValidationMixin:
         self,
         serial: str,
         part: part.models.Part,
-        stock_item: stock.models.StockItem = None,
-    ) -> None:
+        stock_item: Optional[stock.models.StockItem] = None,
+    ) -> Optional[bool]:
         """Validate the supplied serial number.
 
         Arguments:
@@ -171,7 +171,7 @@ class ValidationMixin:
         """
         return None
 
-    def convert_serial_to_int(self, serial: str) -> int:
+    def convert_serial_to_int(self, serial: str) -> Optional[int]:
         """Convert a serial number (string) into an integer representation.
 
         This integer value is used for efficient sorting based on serial numbers.
@@ -192,7 +192,7 @@ class ValidationMixin:
         """
         return None
 
-    def get_latest_serial_number(self, part, **kwargs):
+    def get_latest_serial_number(self, part, **kwargs) -> Optional[str]:
         """Return the 'latest' serial number for a given Part instance.
 
         A plugin which implements this method can either return:
@@ -209,8 +209,8 @@ class ValidationMixin:
         return None
 
     def increment_serial_number(
-        self, serial: str, part: part.models.Part = None, **kwargs
-    ) -> str:
+        self, serial: str, part: Optional[part.models.Part] = None, **kwargs
+    ) -> Optional[str]:
         """Return the next sequential serial based on the provided value.
 
         A plugin which implements this method can either return:
@@ -229,7 +229,7 @@ class ValidationMixin:
 
     def validate_part_parameter(
         self, parameter: part.models.PartParameter, data: str
-    ) -> None:
+    ) -> Optional[bool]:
         """Validate a parameter value.
 
         Arguments:
diff --git a/src/backend/InvenTree/plugin/base/integration/test_mixins.py b/src/backend/InvenTree/plugin/base/integration/test_mixins.py
index ed20b8bd6b..e0251f4805 100644
--- a/src/backend/InvenTree/plugin/base/integration/test_mixins.py
+++ b/src/backend/InvenTree/plugin/base/integration/test_mixins.py
@@ -311,6 +311,7 @@ class APICallMixinTest(BaseMixinDefinition, TestCase):
 
         self.assertTrue(result)
         self.assertNotIn('error', result)
+        assert result is not None
         self.assertEqual(result['name'], 'morpheus')
 
         # api_call with endpoint with leading slash
diff --git a/src/backend/InvenTree/plugin/base/label/test_label_mixin.py b/src/backend/InvenTree/plugin/base/label/test_label_mixin.py
index e0ee950859..f273eeb430 100644
--- a/src/backend/InvenTree/plugin/base/label/test_label_mixin.py
+++ b/src/backend/InvenTree/plugin/base/label/test_label_mixin.py
@@ -113,6 +113,7 @@ class LabelMixinTests(PrintTestMixins, InvenTreeAPITestCase):
         parts = Part.objects.all()[:2]
 
         template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()
+        assert template
 
         self.assertIsNotNone(template)
         self.assertTrue(template.enabled)
@@ -227,6 +228,8 @@ class LabelMixinTests(PrintTestMixins, InvenTreeAPITestCase):
         # Lookup references
         parts = Part.objects.all()[:2]
         template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()
+        assert template
+
         self.do_activate_plugin()
         plugin = registry.get_plugin(self.plugin_ref)
 
diff --git a/src/backend/InvenTree/plugin/broken/broken_file.py b/src/backend/InvenTree/plugin/broken/broken_file.py
index f56932e876..83437025cf 100644
--- a/src/backend/InvenTree/plugin/broken/broken_file.py
+++ b/src/backend/InvenTree/plugin/broken/broken_file.py
@@ -7,4 +7,4 @@ class BrokenFileIntegrationPlugin(InvenTreePlugin):
     """An very broken plugin."""
 
 
-aaa = bb  # noqa: F821
+aaa = bb  # noqa: F821  # type: ignore[unresolved-reference]
diff --git a/src/backend/InvenTree/plugin/helpers.py b/src/backend/InvenTree/plugin/helpers.py
index d03222c38e..cd62e849f7 100644
--- a/src/backend/InvenTree/plugin/helpers.py
+++ b/src/backend/InvenTree/plugin/helpers.py
@@ -51,7 +51,7 @@ class MixinNotImplementedError(NotImplementedError):
 
 def log_registry_error(error, reference: str = 'general'):
     """Log an plugin error."""
-    from plugin import registry
+    from plugin.registry import registry
 
     # make sure the registry is set up
     if reference not in registry.errors:
diff --git a/src/backend/InvenTree/plugin/models.py b/src/backend/InvenTree/plugin/models.py
index b040daa2fd..06923f5ba7 100644
--- a/src/backend/InvenTree/plugin/models.py
+++ b/src/backend/InvenTree/plugin/models.py
@@ -2,6 +2,7 @@
 
 import inspect
 import warnings
+from typing import Optional
 
 from django.conf import settings
 from django.contrib import admin
@@ -219,7 +220,7 @@ class PluginConfig(InvenTree.models.MetadataMixin, models.Model):
         return pkg_name is not None
 
     @property
-    def admin_source(self) -> str:
+    def admin_source(self) -> Optional[str]:
         """Return the path to the javascript file which renders custom admin content for this plugin.
 
         - It is required that the file provides a 'renderPluginSettings' function!
@@ -239,7 +240,7 @@ class PluginConfig(InvenTree.models.MetadataMixin, models.Model):
         return None
 
     @property
-    def admin_context(self) -> dict:
+    def admin_context(self) -> Optional[dict]:
         """Return the context data for the admin integration."""
         if not self.plugin:
             return None
diff --git a/src/backend/InvenTree/plugin/plugin.py b/src/backend/InvenTree/plugin/plugin.py
index a32cc91e91..ec882fd691 100644
--- a/src/backend/InvenTree/plugin/plugin.py
+++ b/src/backend/InvenTree/plugin/plugin.py
@@ -3,7 +3,7 @@
 import inspect
 import warnings
 from datetime import datetime
-from distutils.sysconfig import get_python_lib
+from distutils.sysconfig import get_python_lib  # type: ignore[import]
 from importlib.metadata import PackageNotFoundError, metadata
 from pathlib import Path
 from typing import Optional, Union
@@ -568,8 +568,9 @@ class InvenTreePlugin(VersionMixin, MixinBase, MetaBase):
             package = {}
 
         # process date
-        if package.get('date'):
-            package['date'] = datetime.fromisoformat(package.get('date'))
+        date = package.get('date')
+        if date:
+            package['date'] = datetime.fromisoformat(date)
 
         # set variables
         self.package = package
@@ -608,7 +609,7 @@ class InvenTreePlugin(VersionMixin, MixinBase, MetaBase):
 
         return url
 
-    def get_admin_source(self) -> str:
+    def get_admin_source(self) -> Union[str, None]:
         """Return a path to a JavaScript file which contains custom UI settings.
 
         The frontend code expects that this file provides a function named 'renderPluginSettings'.
@@ -618,7 +619,7 @@ class InvenTreePlugin(VersionMixin, MixinBase, MetaBase):
 
         return self.plugin_static_file(self.ADMIN_SOURCE)
 
-    def get_admin_context(self) -> dict:
+    def get_admin_context(self) -> Union[dict, None]:
         """Return a context dictionary for the admin panel settings.
 
         This is an optional method which can be overridden by the plugin.
diff --git a/src/backend/InvenTree/plugin/registry.py b/src/backend/InvenTree/plugin/registry.py
index ca3fc9d743..4b3af95cc7 100644
--- a/src/backend/InvenTree/plugin/registry.py
+++ b/src/backend/InvenTree/plugin/registry.py
@@ -121,12 +121,12 @@ class PluginsRegistry:
         self.ready = False  # Marks if the registry is ready to be used
 
         # Keep an internal hash of the plugin registry state
-        self.registry_hash = None
+        self.registry_hash: Optional[str] = None
 
         self.plugin_modules: list[InvenTreePlugin] = []  # Holds all discovered plugins
         self.mixin_modules: dict[str, Any] = {}  # Holds all discovered mixins
 
-        self.errors = {}  # Holds errors discovered during loading
+        self.errors: dict[str, list[Any]] = {}  # Holds errors discovered during loading
 
         self.loading_lock = Lock()  # Lock to prevent multiple loading at the same time
 
@@ -289,7 +289,7 @@ class PluginsRegistry:
 
     @registry_entrypoint(default_value=[])
     def with_mixin(
-        self, mixin: str, active: bool = True, builtin: Optional[bool] = None
+        self, mixin: str, active: Optional[bool] = True, builtin: Optional[bool] = None
     ) -> list[InvenTreePlugin]:
         """Returns reference to all plugins that have a specified mixin enabled.
 
@@ -764,9 +764,9 @@ class PluginsRegistry:
                     f"Plugin '{p}' is not compatible with the current InvenTree version {v}"
                 )
                 if v := plg_i.MIN_VERSION:
-                    _msg += _(f'Plugin requires at least version {v}')
+                    _msg += _(f'Plugin requires at least version {v}')  # type: ignore[unsupported-operator]
                 if v := plg_i.MAX_VERSION:
-                    _msg += _(f'Plugin requires at most version {v}')
+                    _msg += _(f'Plugin requires at most version {v}')  # type: ignore[unsupported-operator]
                 # Log to error stack
                 log_registry_error(_msg, reference=f'{p}:init_plugin')
             else:
@@ -809,7 +809,7 @@ class PluginsRegistry:
 
                         logger.exception(
                             '[PLUGIN] Encountered an error with %s:\n%s',
-                            error.path,
+                            getattr(error, 'path', None),
                             str(error),
                         )
 
@@ -1084,11 +1084,14 @@ def _load_source(modname, filename):
 
     # loader = importlib.machinery.SourceFileLoader(modname, filename)
     spec = importlib.util.spec_from_file_location(modname, filename)  # , loader=loader)
+    if spec is None:
+        raise ImportError(f"Cannot find module '{modname}'")  # pragma: no cover
     module = importlib.util.module_from_spec(spec)
 
     sys.modules[module.__name__] = module
 
-    if spec.loader:
-        spec.loader.exec_module(module)
+    loader = spec.loader
+    if loader is not None:
+        loader.exec_module(module)
 
     return module
diff --git a/src/backend/InvenTree/plugin/test_plugin.py b/src/backend/InvenTree/plugin/test_plugin.py
index d07b30ee8c..cdabd46477 100644
--- a/src/backend/InvenTree/plugin/test_plugin.py
+++ b/src/backend/InvenTree/plugin/test_plugin.py
@@ -7,6 +7,7 @@ import tempfile
 import textwrap
 from datetime import datetime
 from pathlib import Path
+from typing import Optional
 from unittest import mock
 from unittest.mock import patch
 
@@ -204,7 +205,9 @@ class InvenTreePluginTests(TestCase):
         self.assertFalse(self.plugin_version.check_version([0, 1, 4]))
 
         plug = registry.plugins_full.get('sampleversion')
-        self.assertEqual(plug.is_active(), False)
+        self.assertIsNotNone(plug)
+        if plug:
+            self.assertEqual(plug.is_active(), False)
 
 
 class RegistryTests(TestQueryMixin, PluginRegistryMixin, TestCase):
@@ -251,7 +254,7 @@ class RegistryTests(TestQueryMixin, PluginRegistryMixin, TestCase):
     def test_folder_loading(self):
         """Test that plugins in folders outside of BASE_DIR get loaded."""
         # Run in temporary directory -> always a new random name
-        with tempfile.TemporaryDirectory() as tmp:
+        with tempfile.TemporaryDirectory() as tmp:  # type: ignore[no-matching-overload]
             # Fill directory with sample data
             new_dir = Path(tmp).joinpath('mock')
             shutil.copytree(self.mockDir(), new_dir)
@@ -400,7 +403,7 @@ class RegistryTests(TestQueryMixin, PluginRegistryMixin, TestCase):
 
         def create_plugin_file(
             version: str, enabled: bool = True, reload: bool = True
-        ) -> str:
+        ) -> Optional[str]:
             """Create a plugin file with the given version.
 
             Arguments:
diff --git a/src/backend/InvenTree/report/api.py b/src/backend/InvenTree/report/api.py
index ef29212aa9..d54ea59d96 100644
--- a/src/backend/InvenTree/report/api.py
+++ b/src/backend/InvenTree/report/api.py
@@ -6,8 +6,9 @@ from django.utils.decorators import method_decorator
 from django.utils.translation import gettext_lazy as _
 from django.views.decorators.cache import never_cache
 
-from django_filters import rest_framework as rest_filters
+import django_filters.rest_framework.filters as rest_filters
 from django_filters.rest_framework import DjangoFilterBackend
+from django_filters.rest_framework.filterset import FilterSet
 from rest_framework.generics import GenericAPIView
 from rest_framework.response import Response
 
@@ -31,7 +32,7 @@ class TemplatePermissionMixin:
     permission_classes = [InvenTree.permissions.IsStaffOrReadOnlyScope]
 
 
-class ReportFilterBase(rest_filters.FilterSet):
+class ReportFilterBase(FilterSet):
     """Base filter class for label and report templates."""
 
     enabled = rest_filters.BooleanFilter()
diff --git a/src/backend/InvenTree/report/apps.py b/src/backend/InvenTree/report/apps.py
index a149a2fb0e..001268dc19 100644
--- a/src/backend/InvenTree/report/apps.py
+++ b/src/backend/InvenTree/report/apps.py
@@ -67,7 +67,7 @@ class ReportConfig(AppConfig):
     def cleanup(self):
         """Cleanup old label and report outputs."""
         try:
-            from report.tasks import cleanup_old_report_outputs
+            from report.tasks import cleanup_old_report_outputs  # type: ignore[import]
 
             cleanup_old_report_outputs()
         except Exception:
diff --git a/src/backend/InvenTree/report/models.py b/src/backend/InvenTree/report/models.py
index 1e26114e5e..b445ae1226 100644
--- a/src/backend/InvenTree/report/models.py
+++ b/src/backend/InvenTree/report/models.py
@@ -238,7 +238,7 @@ class ReportTemplateBase(MetadataMixin, InvenTree.models.InvenTreeModel):
         ),
     )
 
-    def generate_filename(self, context, **kwargs):
+    def generate_filename(self, context, **kwargs) -> str:
         """Generate a filename for this report."""
         template_string = Template(self.filename_pattern)
 
@@ -491,7 +491,7 @@ class ReportTemplate(TemplateUploadMixin, ReportTemplateBase):
         debug_mode = get_global_setting('REPORT_DEBUG_MODE', False)
 
         # Start with a default report name
-        report_name = None
+        report_name: Optional[str] = None
 
         # If a DataOutput object is not provided, create a new one
         if not output:
@@ -608,6 +608,9 @@ class ReportTemplate(TemplateUploadMixin, ReportTemplateBase):
                 'path': request.path if request else None,
             })
 
+        if not report_name:
+            report_name = ''  # pragma: no cover
+
         if not report_name.endswith('.pdf'):
             report_name += '.pdf'
 
@@ -695,7 +698,7 @@ class LabelTemplate(TemplateUploadMixin, ReportTemplateBase):
     def get_context(self, instance, request=None, **kwargs):
         """Supply context data to the label template for rendering."""
         base_context = super().get_context(instance, request, **kwargs)
-        label_context: LabelContextExtension = {
+        label_context: LabelContextExtension = {  # type: ignore[invalid-assignment]
             'width': self.width,
             'height': self.height,
             'page_style': None,
diff --git a/src/backend/InvenTree/report/templatetags/barcode.py b/src/backend/InvenTree/report/templatetags/barcode.py
index 75237bbd7a..9a87adb3b3 100644
--- a/src/backend/InvenTree/report/templatetags/barcode.py
+++ b/src/backend/InvenTree/report/templatetags/barcode.py
@@ -4,6 +4,7 @@ from django import template
 from django.utils.safestring import mark_safe
 
 import barcode as python_barcode
+import barcode.writer as python_barcode_writer
 import qrcode.constants as ECL
 from PIL import Image, ImageColor
 from qrcode.main import QRCode
@@ -122,7 +123,7 @@ def barcode(data: str, barcode_class='code128', **kwargs) -> str:
 
     data = str(data).zfill(constructor.digits)
 
-    writer = python_barcode.writer.ImageWriter
+    writer = python_barcode_writer.ImageWriter
 
     barcode_image = constructor(data, writer=writer())
 
@@ -148,7 +149,7 @@ def datamatrix(data: str, **kwargs) -> str:
     Returns:
         image (str): base64 encoded image data
     """
-    from ppf.datamatrix import DataMatrix
+    from ppf.datamatrix.datamatrix import DataMatrix
 
     data = str(data).strip()
 
diff --git a/src/backend/InvenTree/report/templatetags/report.py b/src/backend/InvenTree/report/templatetags/report.py
index 2977f950da..f1542fad5e 100644
--- a/src/backend/InvenTree/report/templatetags/report.py
+++ b/src/backend/InvenTree/report/templatetags/report.py
@@ -50,7 +50,7 @@ def filter_queryset(queryset: QuerySet, **kwargs) -> QuerySet:
 
 
 @register.simple_tag()
-def filter_db_model(model_name: str, **kwargs) -> QuerySet:
+def filter_db_model(model_name: str, **kwargs) -> Optional[QuerySet]:
     """Filter a database model based on the provided keyword arguments.
 
     Arguments:
@@ -102,7 +102,7 @@ def getindex(container: list, index: int) -> Any:
 
 
 @register.simple_tag()
-def getkey(container: dict, key: str, backup_value: Optional[any] = None) -> Any:
+def getkey(container: dict, key: str, backup_value: Optional[Any] = None) -> Any:
     """Perform key lookup in the provided dict object.
 
     This function is provided to get around template rendering limitations.
@@ -301,14 +301,13 @@ def part_image(part: Part, preview: bool = False, thumbnail: bool = False, **kwa
     if type(part) is not Part:
         raise TypeError(_('part_image tag requires a Part instance'))
 
-    if not part.image:
+    part_img = part.image
+    if not part_img:
         img = None
     elif preview:
-        img = None if not hasattr(part.image, 'preview') else part.image.preview.name
+        img = None if not hasattr(part.image, 'preview') else part_img.preview.name
     elif thumbnail:
-        img = (
-            None if not hasattr(part.image, 'thumbnail') else part.image.thumbnail.name
-        )
+        img = None if not hasattr(part.image, 'thumbnail') else part_img.thumbnail.name
     else:
         img = part.image.name
 
@@ -316,7 +315,7 @@ def part_image(part: Part, preview: bool = False, thumbnail: bool = False, **kwa
 
 
 @register.simple_tag()
-def part_parameter(part: Part, parameter_name: str) -> str:
+def part_parameter(part: Part, parameter_name: str) -> Optional[str]:
     """Return a PartParameter object for the given part and parameter name.
 
     Arguments:
@@ -348,12 +347,15 @@ def company_image(
     if type(company) is not Company:
         raise TypeError(_('company_image tag requires a Company instance'))
 
-    if preview:
-        img = company.image.preview.name
+    cmp_img = company.image
+    if not cmp_img:
+        img = None
+    elif preview:
+        img = cmp_img.preview.name
     elif thumbnail:
-        img = company.image.thumbnail.name
+        img = cmp_img.thumbnail.name
     else:
-        img = company.image.name
+        img = cmp_img.name
 
     return uploaded_image(img, **kwargs)
 
diff --git a/src/backend/InvenTree/report/tests.py b/src/backend/InvenTree/report/tests.py
index b6ceba959c..fcd5efe40a 100644
--- a/src/backend/InvenTree/report/tests.py
+++ b/src/backend/InvenTree/report/tests.py
@@ -84,6 +84,7 @@ class ReportTest(InvenTreeAPITestCase):
         # Filter by items
         part_pk = Part.objects.first().pk
         report = ReportTemplate.objects.filter(model_type='part').first()
+        assert report
 
         try:
             response = self.get(
@@ -236,6 +237,7 @@ class ReportTest(InvenTreeAPITestCase):
         url = reverse('api-report-template-list')
 
         template = ReportTemplate.objects.first()
+        assert template
 
         detail_url = reverse('api-report-template-detail', kwargs={'pk': template.pk})
 
@@ -415,6 +417,7 @@ class PrintTestMixins:
 
         qs = qs.objects.all()
         template = mdl.objects.filter(enabled=True, model_type=model_type).first()
+        assert template
         plugin = registry.get_plugin(self.plugin_ref)
 
         # Single page printing
@@ -475,6 +478,7 @@ class TestReportTest(PrintTestMixins, ReportTest):
         template = ReportTemplate.objects.filter(
             enabled=True, model_type='stockitem'
         ).first()
+        assert template
 
         self.assertIsNotNone(template)
 
diff --git a/src/backend/InvenTree/stock/api.py b/src/backend/InvenTree/stock/api.py
index a3aadaa99d..3c17a1afdd 100644
--- a/src/backend/InvenTree/stock/api.py
+++ b/src/backend/InvenTree/stock/api.py
@@ -9,7 +9,8 @@ from django.db.models import F, Q
 from django.urls import include, path
 from django.utils.translation import gettext_lazy as _
 
-from django_filters import rest_framework as rest_filters
+import django_filters.rest_framework.filters as rest_filters
+from django_filters.rest_framework.filterset import FilterSet
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import extend_schema, extend_schema_field
 from rest_framework import status
@@ -257,7 +258,7 @@ class StockMerge(CreateAPI):
         return ctx
 
 
-class StockLocationFilter(rest_filters.FilterSet):
+class StockLocationFilter(FilterSet):
     """Base class for custom API filters for the StockLocation endpoint."""
 
     class Meta:
@@ -425,11 +426,11 @@ class StockLocationDetail(StockLocationMixin, CustomRetrieveUpdateDestroyAPI):
         return super().destroy(
             request,
             *args,
-            **dict(
-                kwargs,
-                delete_sub_locations=delete_sub_locations,
-                delete_stock_items=delete_stock_items,
-            ),
+            **{
+                **kwargs,
+                'delete_sub_locations': delete_sub_locations,
+                'delete_stock_items': delete_stock_items,
+            },
         )
 
 
@@ -505,7 +506,7 @@ class StockLocationTypeDetail(RetrieveUpdateDestroyAPI):
         return queryset
 
 
-class StockFilter(rest_filters.FilterSet):
+class StockFilter(FilterSet):
     """FilterSet for StockItem LIST API."""
 
     class Meta:
@@ -1339,7 +1340,7 @@ class StockItemTestResultDetail(StockItemTestResultMixin, RetrieveUpdateDestroyA
     """Detail endpoint for StockItemTestResult."""
 
 
-class StockItemTestResultFilter(rest_filters.FilterSet):
+class StockItemTestResultFilter(FilterSet):
     """API filter for the StockItemTestResult list."""
 
     class Meta:
diff --git a/src/backend/InvenTree/stock/filters.py b/src/backend/InvenTree/stock/filters.py
index 1e6900f36f..0baf125875 100644
--- a/src/backend/InvenTree/stock/filters.py
+++ b/src/backend/InvenTree/stock/filters.py
@@ -1,12 +1,14 @@
 """Custom query filters for the Stock models."""
 
+from typing import Optional
+
 from django.db.models import F, Func, IntegerField, OuterRef, Q, Subquery
 from django.db.models.functions import Coalesce
 
 import stock.models
 
 
-def annotate_location_items(filter: Q = None):
+def annotate_location_items(filter: Optional[Q] = None):
     """Construct a queryset annotation which returns the number of stock items in a particular location.
 
     - Includes items in subcategories also
diff --git a/src/backend/InvenTree/stock/generators.py b/src/backend/InvenTree/stock/generators.py
index a52f4518ed..526617395e 100644
--- a/src/backend/InvenTree/stock/generators.py
+++ b/src/backend/InvenTree/stock/generators.py
@@ -1,6 +1,7 @@
 """Generator functions for the stock app."""
 
 from inspect import signature
+from typing import Optional
 
 from django.core.exceptions import ValidationError
 
@@ -78,7 +79,7 @@ def generate_batch_code(**kwargs):
     return Template(batch_template).render(context)
 
 
-def generate_serial_number(part=None, quantity=1, **kwargs) -> str:
+def generate_serial_number(part=None, quantity=1, **kwargs) -> Optional[str]:
     """Generate a default 'serial number' for a new StockItem."""
     quantity = quantity or 1
 
diff --git a/src/backend/InvenTree/stock/migrations/0061_auto_20210511_0911.py b/src/backend/InvenTree/stock/migrations/0061_auto_20210511_0911.py
index ba44e9c1bd..e5d2b82399 100644
--- a/src/backend/InvenTree/stock/migrations/0061_auto_20210511_0911.py
+++ b/src/backend/InvenTree/stock/migrations/0061_auto_20210511_0911.py
@@ -51,10 +51,10 @@ def update_history(apps, schema_editor):
 
             q = entry.quantity
 
-            if idx == 0 or not q == quantity:
+            if idx == 0 or q != quantity:
 
                 try:
-                    deltas['quantity']: float(q)
+                    deltas['quantity']= float(q)
                     updated = True
                 except Exception:
                     print(f"WARNING: Error converting quantity '{q}'")
diff --git a/src/backend/InvenTree/stock/models.py b/src/backend/InvenTree/stock/models.py
index 724251053a..5a0ce08244 100644
--- a/src/backend/InvenTree/stock/models.py
+++ b/src/backend/InvenTree/stock/models.py
@@ -667,7 +667,7 @@ class StockItem(
         return items
 
     @staticmethod
-    def convert_serial_to_int(serial: str) -> int:
+    def convert_serial_to_int(serial: str) -> Optional[int]:
         """Convert the provided serial number to an integer value.
 
         This function hooks into the plugin system to allow for custom serial number conversion.
@@ -1784,7 +1784,7 @@ class StockItem(
         self,
         entry_type: int,
         user: User,
-        deltas: dict | None = None,
+        deltas: Optional[dict] = None,
         notes: str = '',
         commit: bool = True,
         **kwargs,
diff --git a/src/backend/InvenTree/stock/serializers.py b/src/backend/InvenTree/stock/serializers.py
index 14be37b9c8..02ffc1b595 100644
--- a/src/backend/InvenTree/stock/serializers.py
+++ b/src/backend/InvenTree/stock/serializers.py
@@ -20,6 +20,7 @@ import build.models
 import company.models
 import company.serializers as company_serializers
 import InvenTree.helpers
+import InvenTree.ready
 import InvenTree.serializers
 import order.models
 import part.filters as part_filters
diff --git a/src/backend/InvenTree/stock/test_api.py b/src/backend/InvenTree/stock/test_api.py
index 051f555683..00171de588 100644
--- a/src/backend/InvenTree/stock/test_api.py
+++ b/src/backend/InvenTree/stock/test_api.py
@@ -2079,6 +2079,7 @@ class StockTestResultTest(StockAPITestCase):
         url = reverse('api-stock-test-result-list')
 
         test_template = PartTestTemplate.objects.first()
+        assert test_template
 
         test_template.choices = 'AA, BB, CC'
         test_template.save()
diff --git a/src/backend/InvenTree/users/models.py b/src/backend/InvenTree/users/models.py
index 3c59449cd1..99d75ccb8c 100644
--- a/src/backend/InvenTree/users/models.py
+++ b/src/backend/InvenTree/users/models.py
@@ -47,7 +47,9 @@ User.add_to_class('__str__', user_model_str)  # Overriding User.__str__
 
 
 if settings.LDAP_AUTH:
-    from django_auth_ldap.backend import populate_user
+    from django_auth_ldap.backend import (  # type: ignore[unresolved-import]
+        populate_user,
+    )
 
     @receiver(populate_user)
     def create_email_address(user, **kwargs):
diff --git a/src/backend/InvenTree/users/permissions.py b/src/backend/InvenTree/users/permissions.py
index fd3d68a3ad..c4dd898ed6 100644
--- a/src/backend/InvenTree/users/permissions.py
+++ b/src/backend/InvenTree/users/permissions.py
@@ -31,8 +31,8 @@ def get_model_permission_string(model: models.Model, permission: str) -> str:
     Returns:
         str: The permission string (e.g. 'part.view_part')
     """
-    model, app = split_model(model)
-    return f'{app}.{permission}_{model}'
+    _model, _app = split_model(model)
+    return f'{_app}.{permission}_{_model}'
 
 
 def split_permission(app: str, perm: str) -> tuple[str, str]:
diff --git a/src/backend/InvenTree/users/serializers.py b/src/backend/InvenTree/users/serializers.py
index 546177f474..d88b24e72e 100644
--- a/src/backend/InvenTree/users/serializers.py
+++ b/src/backend/InvenTree/users/serializers.py
@@ -281,7 +281,7 @@ class GroupSerializer(InvenTreeModelSerializer):
 class ExtendedUserSerializer(UserSerializer):
     """Serializer for a User with a bit more info."""
 
-    from users.serializers import GroupSerializer
+    # from users.serializers import GroupSerializer
 
     class Meta(UserSerializer.Meta):
         """Metaclass defines serializer fields."""
diff --git a/src/backend/InvenTree/users/tasks.py b/src/backend/InvenTree/users/tasks.py
index 1561f93655..77a903a862 100644
--- a/src/backend/InvenTree/users/tasks.py
+++ b/src/backend/InvenTree/users/tasks.py
@@ -1,5 +1,7 @@
 """Background tasks for the users app."""
 
+from typing import Any
+
 from django.contrib.auth.models import Group, Permission
 from django.contrib.contenttypes.models import ContentType
 
@@ -99,7 +101,7 @@ def update_group_roles(group: Group, debug: bool = False) -> None:
             permissions_to_delete.add(permission_string)
 
     # Pre-fetch all the RuleSet objects
-    rulesets = {
+    rulesets: dict[Any, RuleSet] = {
         r.name: r for r in RuleSet.objects.filter(group=group).prefetch_related('group')
     }
 
diff --git a/src/backend/InvenTree/users/test_api.py b/src/backend/InvenTree/users/test_api.py
index 9728e11435..ce919825e6 100644
--- a/src/backend/InvenTree/users/test_api.py
+++ b/src/backend/InvenTree/users/test_api.py
@@ -131,6 +131,8 @@ class UserAPITests(InvenTreeAPITestCase):
     def test_user_detail(self):
         """Test the UserDetail API endpoint."""
         user = User.objects.first()
+        assert user
+
         url = reverse('api-user-detail', kwargs={'pk': user.pk})
 
         user.is_staff = False
@@ -274,6 +276,7 @@ class UserTokenTests(InvenTreeAPITestCase):
 
         # If we re-generate a token, the value changes
         token = ApiToken.objects.filter(name='cat').first()
+        assert token
 
         # Request the token with the same name
         data = self.get(url, data={'name': 'cat'}, expected_code=200).data
@@ -331,6 +334,7 @@ class UserTokenTests(InvenTreeAPITestCase):
 
         # Grab the token, and update
         token = ApiToken.objects.first()
+        assert token
         self.assertEqual(token.key, token_key)
         self.assertIsNotNone(token.last_seen)
 
diff --git a/src/backend/InvenTree/web/templatetags/__init__.py b/src/backend/InvenTree/web/templatetags/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/backend/InvenTree/web/templatetags/spa_helper.py b/src/backend/InvenTree/web/templatetags/spa_helper.py
index 743d1ef17b..0355ca9060 100644
--- a/src/backend/InvenTree/web/templatetags/spa_helper.py
+++ b/src/backend/InvenTree/web/templatetags/spa_helper.py
@@ -1,6 +1,7 @@
 """Template tag to render SPA imports."""
 
 import json
+import json.decoder
 from pathlib import Path
 from typing import Union
 
diff --git a/src/backend/requirements-dev.in b/src/backend/requirements-dev.in
index 42ddbb679c..d9782f1a19 100644
--- a/src/backend/requirements-dev.in
+++ b/src/backend/requirements-dev.in
@@ -9,3 +9,6 @@ pip-tools                               # Compile pip requirements
 pre-commit                              # Git pre-commit
 setuptools                              # Standard dependency
 pdfminer.six                            # PDF validation
+ty                                      # type checking
+django-types                            # typing
+django-stubs                            # typing
diff --git a/src/backend/requirements-dev.txt b/src/backend/requirements-dev.txt
index 02a601fa6b..8a2a181598 100644
--- a/src/backend/requirements-dev.txt
+++ b/src/backend/requirements-dev.txt
@@ -6,6 +6,7 @@ asgiref==3.9.1 \
     # via
     #   -c src/backend/requirements.txt
     #   django
+    #   django-stubs
 build==1.3.0 \
     --hash=sha256:698edd0ea270bde950f53aed21f3a0135672206f3911e0176261a31e0e07b397 \
     --hash=sha256:7145f0b5061ba90a1500d60bd1b13ca0a8a4cebdd0cc16ed8adf1c0e739f43b4
@@ -326,16 +327,30 @@ django==4.2.24 \
     # via
     #   -c src/backend/requirements.txt
     #   django-slowtests
+    #   django-stubs
+    #   django-stubs-ext
 django-querycount==0.8.3 \
     --hash=sha256:0782484e8a1bd29498fa0195a67106e47cdcc98fafe80cebb1991964077cb694
     # via -r src/backend/requirements-dev.in
 django-slowtests==1.1.1 \
     --hash=sha256:3c6936d420c9df444ac03625b41d97de043c662bbde61fbcd33e4cd407d0c247
     # via -r src/backend/requirements-dev.in
+django-stubs==5.1.3 \
+    --hash=sha256:716758ced158b439213062e52de6df3cff7c586f9f9ad7ab59210efbea5dfe78 \
+    --hash=sha256:8c230bc5bebee6da282ba8a27ad1503c84a0c4cd2f46e63d149e76d2a63e639a
+    # via -r src/backend/requirements-dev.in
+django-stubs-ext==5.1.3 \
+    --hash=sha256:3e60f82337f0d40a362f349bf15539144b96e4ceb4dbd0239be1cd71f6a74ad0 \
+    --hash=sha256:64561fbc53e963cc1eed2c8eb27e18b8e48dcb90771205180fe29fc8a59e55fd
+    # via django-stubs
 django-test-migrations==1.4.0 \
     --hash=sha256:294dff98f6d43d020d4046b971bac5339e7c71458a35e9ad6450c388fe16ed6b \
     --hash=sha256:f0c9c92864ed27d0c9a582e92056637e91227f54bd868a50cb9a1726668c563e
     # via -r src/backend/requirements-dev.in
+django-types==0.20.0 \
+    --hash=sha256:4e55d2c56155e3d69d75def9eb1d95a891303f2ac19fccf6fe8056da4293fae7 \
+    --hash=sha256:a0b5c2c9a1e591684bb21a93b64e50ca6cb2d3eab48f49faff1eac706bd3a9c7
+    # via -r src/backend/requirements-dev.in
 filelock==3.18.0 \
     --hash=sha256:adbc88eabb99d2fec8c9c1b229b171f18afa655400173ddc653d5d01501fb9f2 \
     --hash=sha256:c401f4f8377c4464e6db25fff06205fd89bdd83b65eb0488ed1b160f780e21de
@@ -505,13 +520,44 @@ tomli==2.2.1 \
     #   -c src/backend/requirements.txt
     #   build
     #   coverage
+    #   django-stubs
     #   pip-tools
+ty==0.0.1a20 \
+    --hash=sha256:0b481f26513f38543df514189fb16744690bcba8d23afee95a01927d93b46e36 \
+    --hash=sha256:3c2ace3a22fab4bd79f84c74e3dab26e798bfba7006bea4008d6321c1bd6efc6 \
+    --hash=sha256:3ff75cd4c744d09914e8c9db8d99e02f82c9379ad56b0a3fc4c5c9c923cfa84e \
+    --hash=sha256:726d0738be4459ac7ffae312ba96c5f486d6cbc082723f322555d7cba9397871 \
+    --hash=sha256:7abbe3c02218c12228b1d7c5f98c57240029cc3bcb15b6997b707c19be3908c1 \
+    --hash=sha256:83a7ee12465841619b5eb3ca962ffc7d576bb1c1ac812638681aee241acbfbbe \
+    --hash=sha256:8a138fa4f74e6ed34e9fd14652d132409700c7ff57682c2fed656109ebfba42f \
+    --hash=sha256:8eff8871d6b88d150e2a67beba2c57048f20c090c219f38ed02eebaada04c124 \
+    --hash=sha256:933b65a152f277aa0e23ba9027e5df2c2cc09e18293e87f2a918658634db5f15 \
+    --hash=sha256:b4124ab75e0e6f09fe7bc9df4a77ee43c5e0ef7e61b0c149d7c089d971437cbd \
+    --hash=sha256:b8c4336987a6a781d4392a9fd7b3a39edb7e4f3dd4f860e03f46c932b52aefa2 \
+    --hash=sha256:cad12c857ea4b97bf61e02f6796e13061ccca5e41f054cbd657862d80aa43bae \
+    --hash=sha256:d8ac1c5a14cda5fad1a8b53959d9a5d979fe16ce1cc2785ea8676fed143ac85f \
+    --hash=sha256:e26437772be7f7808868701f2bf9e14e706a6ec4c7d02dbd377ff94d7ba60c11 \
+    --hash=sha256:f153b65c7fcb6b8b59547ddb6353761b3e8d8bb6f0edd15e3e3ac14405949f7a \
+    --hash=sha256:f41e77ff118da3385915e13c3f366b3a2f823461de54abd2e0ca72b170ba0f19 \
+    --hash=sha256:f73a7aca1f0d38af4d6999b375eb00553f3bfcba102ae976756cc142e14f3450 \
+    --hash=sha256:fff51c75ee3f7cc6d7722f2f15789ef8ffe6fd2af70e7269ac785763c906688e
+    # via -r src/backend/requirements-dev.in
+types-psycopg2==2.9.21.20250915 \
+    --hash=sha256:bfeb8f54c32490e7b5edc46215ab4163693192bc90407b4a023822de9239f5c8 \
+    --hash=sha256:eefe5ccdc693fc086146e84c9ba437bb278efe1ef330b299a0cb71169dc6c55f
+    # via django-types
+types-pyyaml==6.0.12.20250915 \
+    --hash=sha256:0f8b54a528c303f0e6f7165687dd33fafa81c807fcac23f632b63aa624ced1d3 \
+    --hash=sha256:e7d4d9e064e89a3b3cae120b4990cd370874d2bf12fa5f46c97018dd5d3c9ab6
+    # via django-stubs
 typing-extensions==4.14.1 \
     --hash=sha256:38b39f4aeeab64884ce9f74c94263ef78f3c22467c8724005483154c26648d36 \
     --hash=sha256:d1e1e3b58374dc93031d6eda2420a48ea44a36c2b4766a4fdeb3710755731d76
     # via
     #   -c src/backend/requirements.txt
     #   asgiref
+    #   django-stubs
+    #   django-stubs-ext
     #   django-test-migrations
 virtualenv==20.33.1 \
     --hash=sha256:07c19bc66c11acab6a5958b815cbcee30891cd1c2ccf53785a28651a0d8d8a67 \
diff --git a/tasks.py b/tasks.py
index 78c56dceed..be2543570b 100644
--- a/tasks.py
+++ b/tasks.py
@@ -77,7 +77,7 @@ def is_pkg_installer_by_path():
 def get_installer(content: Optional[dict] = None):
     """Get the installer for the current environment or a content dict."""
     if content is None:
-        content = os.environ
+        content = dict(os.environ)
     return content.get('INVENTREE_PKG_INSTALLER', None)
 
 
@@ -461,7 +461,9 @@ def check_file_existence(filename: Path, overwrite: bool = False):
 @state_logger('TASK01')
 def plugins(c, uv=False):
     """Installs all plugins as specified in 'plugins.txt'."""
-    from src.backend.InvenTree.InvenTree.config import get_plugin_file
+    from src.backend.InvenTree.InvenTree.config import (  # type: ignore[import]
+        get_plugin_file,
+    )
 
     plugin_file = get_plugin_file()
 
@@ -573,7 +575,9 @@ def rebuild_models(c):
 @task
 def rebuild_thumbnails(c):
     """Rebuild missing image thumbnails."""
-    from src.backend.InvenTree.InvenTree.config import get_media_dir
+    from src.backend.InvenTree.InvenTree.config import (  # type: ignore[import]
+        get_media_dir,
+    )
 
     info(f'Rebuilding image thumbnails in {get_media_dir()}')
     manage(c, 'rebuild_thumbnails', pty=True)
@@ -1165,7 +1169,7 @@ def test_translations(c):
     info('Fill in dummy translations...')
 
     file_path = pathlib.Path(settings.LOCALE_PATHS[0], 'xx', 'LC_MESSAGES', 'django.po')
-    new_file_path = str(file_path) + '_new'
+    new_file_path = Path(str(file_path) + '_new')
 
     # compile regex
     reg = re.compile(
@@ -1303,7 +1307,9 @@ def setup_test(
     path='inventree-demo-dataset',
 ):
     """Setup a testing environment."""
-    from src.backend.InvenTree.InvenTree.config import get_media_dir
+    from src.backend.InvenTree.InvenTree.config import (  # type: ignore[import]
+        get_media_dir,
+    )
 
     if not ignore_update:
         update(c)
@@ -1453,8 +1459,8 @@ def export_definitions(c, basedir: str = ''):
 @task(default=True)
 def version(c):
     """Show the current version of InvenTree."""
-    import src.backend.InvenTree.InvenTree.version as InvenTreeVersion
-    from src.backend.InvenTree.InvenTree.config import (
+    import src.backend.InvenTree.InvenTree.version as InvenTreeVersion  # type: ignore[import]
+    from src.backend.InvenTree.InvenTree.config import (  # type: ignore[import]
         get_backup_dir,
         get_config_file,
         get_media_dir,