[Feature] SalesOrder Auto-Allocate (#12000)

* Add basic auto-allocate functionality

- backend code
- background task
- API endpoint

* Add new endpoint enum

* add frontend components

* Tweak auto-allocate output

* Allow specifying of individual line items

* Tweak error boundary

* Enable bulk-delete of allocated items against sales order

* Refactor stock sorting options

* Allow user to select how to handle serialized stock

* Backport new functionality to BuildOrder allocation

* Refactor sorting options to use enumerated values

* Implement functional unit tests for new feature

* Update API and CHANGELOG

* Additional unit test

* Add playwright testing

* Documentation

* Update docs for build auto-allocate

* Fix dependencies

* Adjust build line filtering

* Fix serializer

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- [#12000](https://github.com/inventree/InvenTree/pull/12000) adds support for auto-allocation of stock items against sales orders. This includes both backend and frontend changes, allowing users to trigger auto-allocation via the API or through the UI. The auto-allocation process will attempt to allocate available stock items to the sales order line items, based on the specified stock sorting and allocation rules.
 - [#11920](https://github.com/inventree/InvenTree/pull/11920) adds support for renaming attachments after they have been uploaded. This includes both backend and frontend changes, allowing users to rename attachments via the API or through the UI.
 - [#11914](https://github.com/inventree/InvenTree/pull/11914) adds a "maximum_stock" field to the Part model, allowing users to specify a maximum preferred stock level for each part. This is used in conjunction with the existing "minimum_stock" field to allow users to define a preferred stock range for each part. The "high_stock" filter has also been added to the Part API endpoint, allowing users to filter parts which are above their maximum stock level.
 - [#11631](https://github.com/inventree/InvenTree/pull/11631) adds "raw_amount" field to the BomItem model, allowing BOM quantities to account for the units of measure of the underlying part.

docs/docs/manufacturing/allocate.md

@@ -80,7 +80,16 @@ The *Deallocate Stock* button can be used to remove all allocations of untracked
 
 ## Automatic Stock Allocation
 
-To speed up the allocation process, the *Auto Allocate* button can be used to allocate untracked stock items to the build. Automatic allocation of stock items does not work in every situation, as a number of criteria must be met.
+To speed up the allocation process, the *Auto Allocate* button can be used to automatically allocate stock items to the build.
+
+!!! info "Background Task"
+    Auto-allocation runs as a background task. The UI will display a progress indicator while the task is running.
+
+#### Selecting Lines to Allocate
+
+By default, auto-allocation processes **all eligible BOM line items** in the build order. To restrict allocation to a subset of lines, select the desired rows in the allocation table before pressing the button — the dialog will indicate how many lines are selected.
+
+#### Auto Allocation Options
 
 The *Automatic Allocation* dialog is presented as shown below:
 
@@ -90,12 +99,16 @@ The *Automatic Allocation* dialog is presented as shown below:
 
 Select the master location where stock items are to be allocated from. Leave this input blank to allocate stock items from any available location.
 
+**Exclude Location**
+
+Exclude stock from a specific location (and all of its sub-locations). Useful for reserving stock in a particular area.
+
 **Interchangeable Stock**
 
 Set this option to *True* to signal that stock items can be used interchangeably. This means that in the case where multiple stock items are available, the auto-allocation routine does not care which stock item it uses.
 
 !!! warning "Take Care"
-    If the *Interchangeable Stock* option is enabled, and there are multiple stock items available, the results of the automatic allocation algorithm may somewhat unexpected.
+    If the *Interchangeable Stock* option is enabled, and there are multiple stock items available, the results of the automatic allocation algorithm may be somewhat unexpected.
 
 !!! info "Example"
     Let's say that we have 5 reels of our *C_100nF_0603* capacitor, each with 4,000 parts available. If we do not mind which of these reels the stock should be taken from, we enable the *Interchangeable Stock* option in the dialog above. In this case, the stock will be allocated from one of these reels, and eventually subtracted from stock when the build is completed.
@@ -104,6 +117,32 @@ Set this option to *True* to signal that stock items can be used interchangeably
 
 Set this option to *True* to allow substitute parts (as specified by the BOM) to be allocated, if the primary parts are not available.
 
+**Optional Items**
+
+Set this option to *True* to include optional BOM line items in the auto-allocation. By default, optional items are not automatically allocated.
+
+**Item Type**
+
+Controls which category of BOM line items is considered for auto-allocation:
+
+| Option | Description |
+| --- | --- |
+| Untracked Items | Only untracked (non-serialized) BOM lines are allocated *(default)* |
+| Tracked Items | Only tracked BOM lines are allocated |
+| All Items | Both tracked and untracked BOM lines are allocated |
+
+**Stock Priority**
+
+Controls the order in which matching stock items are consumed:
+
+| Option | Description |
+| --- | --- |
+| Oldest stock first (FIFO) | Stock items updated least recently are consumed first *(default)* |
+| Newest stock first (LIFO) | Stock items updated most recently are consumed first |
+| Smallest quantity first | Stock items with the lowest available quantity are consumed first |
+| Largest quantity first | Stock items with the highest available quantity are consumed first |
+| Soonest expiry date first | Stock items expiring earliest are consumed first; items with no expiry date are used last |
+
 ## Allocating Tracked Stock
 
 Allocation of tracked stock items is slightly more complex. Instead of being allocated against the *Build Order*, tracked stock items must be allocated against an individual *Build Output*.

docs/docs/sales/sales_order.md

@@ -110,6 +110,79 @@ After shipments were created, user can either:
 
 During the allocation process, user is required to select the desired shipment that will contain the stock items.
 
+### Auto Allocate Stock
+
+To speed up the allocation process, use the *Auto Allocate Stock* button ({{ icon("wand") }}) available in the *Line Items* tab. This automatically finds available stock and creates the required allocations with minimal user interaction.
+
+!!! info "Background Task"
+    Auto-allocation runs as a background task. The UI will display a progress indicator while the task is running.
+
+#### Selecting Lines to Allocate
+
+By default, auto-allocation processes **all unallocated line items** on the order. To restrict allocation to a subset of lines, select the desired rows in the *Line Items* table before pressing the button — the dialog will indicate how many lines are selected.
+
+#### Auto Allocation Options
+
+The auto-allocation dialog provides the following options:
+
+**Source Location**
+
+Restrict stock to a specific location (and all of its sub-locations). Leave blank to consider stock from any location.
+
+**Exclude Location**
+
+Exclude stock from a specific location (and all of its sub-locations). Useful for reserving stock in a particular area.
+
+**Shipment**
+
+Optionally assign all new allocations to a specific pending shipment. Only shipments that have not yet been completed are shown.
+
+**Interchangeable Stock**
+
+When enabled (default), stock may be drawn from multiple stock items or locations to fulfil a single line item. When disabled, a line item is only allocated if a single stock item can cover the entire remaining quantity.
+
+!!! warning "Take Care"
+    Enabling *Interchangeable Stock* means the auto-allocation routine will combine stock from different batches or locations. Review the resulting allocations if traceability is important.
+
+**Stock Priority**
+
+Controls the order in which matching stock items are consumed:
+
+| Option | Description |
+| --- | --- |
+| Oldest stock first (FIFO) | Stock items updated least recently are consumed first *(default)* |
+| Newest stock first (LIFO) | Stock items updated most recently are consumed first |
+| Smallest quantity first | Stock items with the lowest available quantity are consumed first |
+| Largest quantity first | Stock items with the highest available quantity are consumed first |
+| Soonest expiry date first | Stock items expiring earliest are consumed first; items with no expiry date are used last |
+
+**Serialized Stock**
+
+Controls whether serialized stock items are included in the auto-allocation:
+
+| Option | Description |
+| --- | --- |
+| Allow any stock | Both serialized and unserialized stock items are considered *(default)* |
+| Serialized stock only | Only stock items that carry a serial number are allocated |
+| Unserialized stock only | Only stock items without a serial number are allocated |
+
+#### Allocation Behaviour
+
+The auto-allocation routine performs the following steps for each eligible line item:
+
+1. Skips line items for *virtual* parts.
+2. Skips line items that are already fully allocated.
+3. Queries available stock for the line's part, applying any location and serialized-stock filters.
+4. Sorts the candidates according to the chosen *Stock Priority*.
+5. Greedily allocates from each stock item in turn until the remaining quantity for the line is satisfied.
+
+#### Removing Allocations
+
+Individual or multiple allocations can be removed from the *Allocated Stock* tab. Select the allocations to remove and use the *Delete* action.
+
+!!! warning "Shipped Allocations Protected"
+    Allocations that belong to a completed (shipped) shipment cannot be deleted.
+
 ### Check Shipment
 
 Shipments can be marked as "checked" to indicate that the items in the shipment has been verified. To mark a shipment as "checked", open the shipment actions menu, and select the "Check" action:

src/backend/InvenTree/InvenTree/api_version.py

@@ -1,11 +1,16 @@
 """InvenTree API version information."""
 
 # InvenTree API version
-INVENTREE_API_VERSION = 494
+INVENTREE_API_VERSION = 495
 """Increment this API version number whenever there is a significant change to the API that any clients need to know about."""
 
 INVENTREE_API_TEXT = """
 
+v495 -> 2026-05-25 : https://github.com/inventree/InvenTree/pull/12000
+    - Adds "auto-allocate" API endpoint for sales orders
+    - Allow bulk-delete of SalesOrderAllocation objects via the API
+    - Add new allocation options to the Build auto-allocate API endpoint
+
 v494 -> 2026-05-23 : https://github.com/inventree/InvenTree/pull/11990
     - Offload build output operations to a background task, and return a task ID which can be used to monitor the progress of the task
 

src/backend/InvenTree/build/api.py

@@ -886,6 +886,8 @@ class BuildAutoAllocate(BuildOrderContextMixin, CreateAPI):
         serializer.is_valid(raise_exception=True)
         data = serializer.validated_data
 
+        build_lines = data.get('build_lines', [])
+
         # Offload the task to the background worker
         task_id = offload_task(
             auto_allocate_build,
@@ -896,6 +898,8 @@ class BuildAutoAllocate(BuildOrderContextMixin, CreateAPI):
             substitutes=data['substitutes'],
             optional_items=data['optional_items'],
             item_type=data.get('item_type', 'untracked'),
+            stock_sort_by=data['stock_sort_by'],
+            line_ids=[line.pk for line in build_lines] if build_lines else None,
             group='build',
         )
 

src/backend/InvenTree/build/models.py

@@ -1342,6 +1342,8 @@ class Build(
         interchangeable = kwargs.get('interchangeable', False)
         substitutes = kwargs.get('substitutes', True)
         optional_items = kwargs.get('optional_items', False)
+        stock_sort_by = kwargs.get('stock_sort_by', stock.models.STOCK_SORT_DEFAULT)
+        line_ids = kwargs.get('line_ids')
 
         def stock_sort(item, bom_item, variant_parts):
             if item.part == bom_item.sub_part:
@@ -1353,7 +1355,11 @@ class Build(
         new_items = []
 
         # Select only "untracked" line items
-        for line_item in self.untracked_line_items.all():
+        untracked_lines = self.untracked_line_items.all()
+        if line_ids:
+            untracked_lines = untracked_lines.filter(pk__in=line_ids)
+
+        for line_item in untracked_lines:
             # Find the referenced BomItem
             bom_item = line_item.bom_item
 
@@ -1410,13 +1416,22 @@ class Build(
                     location__in=list(sublocations)
                 )
 
+            # Apply secondary ORM ordering before the Python match-quality stable-sort.
+            if stock_sort_by == stock.models.StockSortOrder.EXPIRY_SOONEST:
+                available_stock = available_stock.order_by(
+                    F('expiry_date').asc(nulls_last=True)
+                )
+            else:
+                available_stock = available_stock.order_by(stock_sort_by)
+
             """
             Next, we sort the available stock items with the following priority:
             1. Direct part matches (+1)
             2. Variant part matches (+2)
             3. Substitute part matches (+3)
 
-            This ensures that allocation priority is first given to "direct" parts
+            This ensures that allocation priority is first given to "direct" parts.
+            Python's stable sort preserves the secondary ORM ordering within each group.
             """
             available_stock = sorted(
                 available_stock,

src/backend/InvenTree/build/serializers.py

@@ -27,6 +27,7 @@ import company.serializers
 import InvenTree.helpers
 import part.filters
 import part.serializers as part_serializers
+import stock.models as stock_models
 from common.settings import get_global_setting
 from generic.states.fields import InvenTreeCustomStatusSerializerMixin
 from InvenTree.mixins import DataImportExportSerializerMixin
@@ -1065,6 +1066,24 @@ class BuildAutoAllocationSerializer(serializers.Serializer):
         help_text=_('Select item type to auto-allocate'),
     )
 
+    stock_sort_by = serializers.ChoiceField(
+        default=stock_models.STOCK_SORT_DEFAULT,
+        choices=stock_models.STOCK_SORT_CHOICES,
+        label=_('Stock Priority'),
+        help_text=_('Preferred order in which matching stock items are consumed'),
+    )
+
+    build_lines = serializers.PrimaryKeyRelatedField(
+        queryset=BuildLine.objects.all(),
+        many=True,
+        required=False,
+        default=list,
+        label=_('Build Lines'),
+        help_text=_(
+            'Limit allocation to these build lines (leave blank to allocate all lines)'
+        ),
+    )
+
 
 class BuildItemSerializer(
     FilterableSerializerMixin, DataImportExportSerializerMixin, InvenTreeModelSerializer

src/backend/InvenTree/build/test_api.py

@@ -12,7 +12,7 @@ from build.status_codes import BuildStatus
 from common.settings import set_global_setting
 from InvenTree.unit_test import InvenTreeAPITestCase
 from part.models import BomItem, Part
-from stock.models import StockItem
+from stock.models import StockItem, StockLocation, StockSortOrder
 from stock.status_codes import StockStatus
 
 
@@ -1811,3 +1811,162 @@ class BuildConsumeTest(BuildAPITest):
 
         for line in self.build.build_lines.all():
             self.assertEqual(line.consumed, 100)
+
+
+class BuildAutoAllocateAPITest(InvenTreeAPITestCase):
+    """API integration tests for BuildAutoAllocate endpoint back-ports (stock_sort_by, build_lines)."""
+
+    fixtures = ['company', 'users']
+
+    roles = ['build.add', 'build.change']
+
+    @classmethod
+    def setUpTestData(cls):
+        """Create shared parts, locations and build data for all tests."""
+        super().setUpTestData()
+
+        cls.assembly = Part.objects.create(
+            name='AutoAlloc Assembly', description='', assembly=True
+        )
+        cls.component = Part.objects.create(
+            name='AutoAlloc Component', description='', component=True
+        )
+        cls.component_b = Part.objects.create(
+            name='AutoAlloc Component B', description='', component=True
+        )
+
+        cls.loc_a = StockLocation.objects.create(name='BuildShelf A')
+        cls.loc_b = StockLocation.objects.create(name='BuildShelf B')
+
+    def _next_ref(self):
+        """Return a valid Build reference using the system-generated next value."""
+        return Build.generate_batch_code()
+
+    def _make_build(self, quantity=10):
+        """Create a fresh Build with one untracked BOM line (component only)."""
+        build = Build.objects.create(
+            part=self.assembly,
+            reference=f'BO-{9000 + Build.objects.count():04d}',
+            quantity=quantity,
+        )
+        BomItem.objects.create(part=self.assembly, sub_part=self.component, quantity=1)
+        build.create_build_line_items()
+        return build
+
+    def _url(self, pk):
+        return reverse('api-build-auto-allocate', kwargs={'pk': pk})
+
+    def _create_build_two_lines(self, quantity=5):
+        """Create a Build with two untracked BOM lines (component + component_b)."""
+        build = Build.objects.create(
+            part=self.assembly,
+            reference=f'BO-{9000 + Build.objects.count():04d}',
+            quantity=quantity,
+        )
+        BomItem.objects.create(part=self.assembly, sub_part=self.component, quantity=1)
+        BomItem.objects.create(
+            part=self.assembly, sub_part=self.component_b, quantity=1
+        )
+        build.create_build_line_items()
+        return build
+
+    # ------------------------------------------------------------------
+    # Validation
+    # ------------------------------------------------------------------
+
+    def test_invalid_stock_sort_by_rejected(self):
+        """An unrecognised stock_sort_by value is rejected with 400."""
+        build = self._make_build()
+        self.post(
+            self._url(build.pk), {'stock_sort_by': 'not_valid'}, expected_code=400
+        )
+
+    # ------------------------------------------------------------------
+    # stock_sort_by behaviour
+    # ------------------------------------------------------------------
+
+    def test_stock_sort_by_quantity_asc(self):
+        """stock_sort_by=QUANTITY_ASC consumes the smallest lot first."""
+        build = self._make_build(quantity=15)
+        small = StockItem.objects.create(part=self.component, quantity=5)
+        StockItem.objects.create(part=self.component, quantity=100)
+
+        self.post(
+            self._url(build.pk),
+            {
+                'stock_sort_by': str(StockSortOrder.QUANTITY_ASC),
+                'interchangeable': True,
+            },
+            expected_code=200,
+        )
+
+        allocs = BuildItem.objects.filter(build_line__build=build)
+        self.assertTrue(any(a.stock_item == small and a.quantity == 5 for a in allocs))
+
+    def test_stock_sort_by_quantity_desc(self):
+        """stock_sort_by=QUANTITY_DESC consumes the largest lot first, covering requirement in one allocation."""
+        build = self._make_build(quantity=15)
+        StockItem.objects.create(part=self.component, quantity=5)
+        large = StockItem.objects.create(part=self.component, quantity=100)
+
+        self.post(
+            self._url(build.pk),
+            {
+                'stock_sort_by': str(StockSortOrder.QUANTITY_DESC),
+                'interchangeable': True,
+            },
+            expected_code=200,
+        )
+
+        allocs = BuildItem.objects.filter(build_line__build=build)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().stock_item, large)
+        self.assertEqual(allocs.first().quantity, 15)
+
+    # ------------------------------------------------------------------
+    # build_lines filtering
+    # ------------------------------------------------------------------
+
+    def test_build_lines_subset_only_allocates_selected_lines(self):
+        """When build_lines is specified only those lines are allocated."""
+        build = self._create_build_two_lines()
+
+        StockItem.objects.create(part=self.component, quantity=50)
+        StockItem.objects.create(part=self.component_b, quantity=50)
+
+        line_a = build.build_lines.filter(bom_item__sub_part=self.component).first()
+
+        self.post(
+            self._url(build.pk),
+            {'build_lines': [line_a.pk], 'interchangeable': True},
+            expected_code=200,
+        )
+
+        alloc_a = BuildItem.objects.filter(
+            build_line__build=build, stock_item__part=self.component
+        )
+        alloc_b = BuildItem.objects.filter(
+            build_line__build=build, stock_item__part=self.component_b
+        )
+
+        self.assertTrue(alloc_a.exists())
+        self.assertFalse(alloc_b.exists())
+
+    def test_build_lines_empty_allocates_all(self):
+        """When build_lines is omitted, all untracked lines are allocated."""
+        build = self._create_build_two_lines()
+
+        StockItem.objects.create(part=self.component, quantity=50)
+        StockItem.objects.create(part=self.component_b, quantity=50)
+
+        self.post(self._url(build.pk), {'interchangeable': True}, expected_code=200)
+
+        alloc_a = BuildItem.objects.filter(
+            build_line__build=build, stock_item__part=self.component
+        )
+        alloc_b = BuildItem.objects.filter(
+            build_line__build=build, stock_item__part=self.component_b
+        )
+
+        self.assertTrue(alloc_a.exists())
+        self.assertTrue(alloc_b.exists())

src/backend/InvenTree/order/api.py

@@ -31,6 +31,7 @@ import stock.serializers as stock_serializers
 from data_exporter.mixins import DataExportViewMixin
 from generic.states.api import StatusView
 from InvenTree.api import (
+    BulkDeleteMixin,
     BulkUpdateMixin,
     ListCreateDestroyAPIView,
     ParameterListMixin,
@@ -1170,6 +1171,50 @@ class SalesOrderAllocate(SalesOrderContextMixin, CreateAPI):
     serializer_class = serializers.SalesOrderShipmentAllocationSerializer
 
 
+class SalesOrderAutoAllocate(SalesOrderContextMixin, CreateAPI):
+    """API endpoint to automatically allocate stock against a SalesOrder.
+
+    - Offloads work to a background task and returns task detail
+    """
+
+    serializer_class = serializers.SalesOrderAutoAllocationSerializer
+
+    @extend_schema(responses={200: common.serializers.TaskDetailSerializer})
+    def post(self, *args, **kwargs):
+        """Validate parameters and offload auto-allocation to a background task."""
+        from InvenTree.tasks import offload_task
+        from order.tasks import auto_allocate_sales_order
+
+        order_obj = self.get_object()
+        serializer = self.get_serializer(data=self.request.data)
+        serializer.is_valid(raise_exception=True)
+        data = serializer.validated_data
+
+        # Extract related models from the validated data
+        location = data.get('location')
+        exclude_location = data.get('exclude_location')
+        shipment = data.get('shipment')
+        line_items = data.get('line_items', [])
+
+        # Offload to the background worker
+        # Note: We provide the model ID values, not the model instances
+        task_id = offload_task(
+            auto_allocate_sales_order,
+            order_obj.pk,
+            location_id=location.pk if location else None,
+            exclude_location_id=exclude_location.pk if exclude_location else None,
+            shipment_id=shipment.pk if shipment else None,
+            line_ids=[item.pk for item in line_items] if line_items else None,
+            interchangeable=data['interchangeable'],
+            stock_sort_by=data['stock_sort_by'],
+            serialized_stock=data['serialized_stock'],
+            group='sales_order',
+        )
+
+        response = common.serializers.TaskDetailSerializer.from_task(task_id).data
+        return Response(response, status=response['http_status'])
+
+
 class SalesOrderAllocationFilter(FilterSet):
     """Custom filterset for the SalesOrderAllocationList endpoint."""
 
@@ -1300,7 +1345,11 @@ class SalesOrderAllocationOutputOptions(OutputConfiguration):
 
 
 class SalesOrderAllocationList(
-    SalesOrderAllocationMixin, BulkUpdateMixin, OutputOptionsMixin, ListAPI
+    SalesOrderAllocationMixin,
+    BulkDeleteMixin,
+    BulkUpdateMixin,
+    OutputOptionsMixin,
+    ListAPI,
 ):
     """API endpoint for listing SalesOrderAllocation objects."""
 
@@ -1308,6 +1357,10 @@ class SalesOrderAllocationList(
     filter_backends = SEARCH_ORDER_FILTER
     output_options = SalesOrderAllocationOutputOptions
 
+    def filter_delete_queryset(self, queryset, request):
+        """Prevent deletion of allocations that have already been shipped."""
+        return queryset.filter(shipment__shipment_date__isnull=True)
+
     ordering_fields = [
         'quantity',
         'part',
@@ -2582,6 +2635,11 @@ order_api_urls = [
                         SalesOrderAllocateSerials.as_view(),
                         name='api-so-allocate-serials',
                     ),
+                    path(
+                        'auto-allocate/',
+                        SalesOrderAutoAllocate.as_view(),
+                        name='api-so-auto-allocate',
+                    ),
                     path('hold/', SalesOrderHold.as_view(), name='api-so-hold'),
                     path('cancel/', SalesOrderCancel.as_view(), name='api-so-cancel'),
                     path('issue/', SalesOrderIssue.as_view(), name='api-so-issue'),

src/backend/InvenTree/order/models.py

@@ -1317,6 +1317,18 @@ class PurchaseOrder(TotalPriceMixin, Order):
         )
 
 
+STOCK_SORT_CHOICES = stock.models.STOCK_SORT_CHOICES
+STOCK_SORT_DEFAULT = stock.models.STOCK_SORT_DEFAULT
+
+SERIALIZED_STOCK_CHOICES = [
+    ('any', _('Allow any stock (serialized or unserialized)')),
+    ('serialized', _('Serialized stock only')),
+    ('unserialized', _('Unserialized stock only')),
+]
+
+SERIALIZED_STOCK_DEFAULT = 'any'
+
+
 class SalesOrder(TotalPriceMixin, Order):
     """A SalesOrder represents a list of goods shipped outwards to a customer."""
 
@@ -1469,6 +1481,130 @@ class SalesOrder(TotalPriceMixin, Order):
         """Return true if any lines in the order are over-allocated."""
         return any(line.is_overallocated() for line in self.lines.all())
 
+    @transaction.atomic
+    def auto_allocate_stock(
+        self,
+        location: Optional[stock.models.StockLocation] = None,
+        exclude_location: Optional[stock.models.StockLocation] = None,
+        shipment: Optional['SalesOrderShipment'] = None,
+        line_ids: Optional[list] = None,
+        **kwargs,
+    ):
+        """Automatically allocate stock items against this SalesOrder.
+
+        For each unallocated line item, finds available stock for
+        the line's part, filtered and sorted according to the supplied kwargs, then
+        creates SalesOrderAllocation records in bulk.
+
+        Arguments:
+            location: If provided, only consider stock within this location tree.
+            exclude_location: If provided, exclude stock within this location tree.
+            shipment: Optional shipment to assign allocations to.
+            line_ids: If provided, only allocate against these specific line item PKs.
+
+        Kwargs:
+            interchangeable (bool): If True (default), consume stock from multiple
+                items/locations to satisfy a line. If False, only allocate when a
+                single item can cover the full remaining quantity.
+        """
+        stock_sort_by = kwargs.get('stock_sort_by', STOCK_SORT_DEFAULT)
+        interchangeable = kwargs.get('interchangeable', True)
+        serialized_stock = kwargs.get('serialized_stock', SERIALIZED_STOCK_DEFAULT)
+
+        new_allocations = []
+
+        lines = self.lines.all()
+        if line_ids:
+            lines = lines.filter(pk__in=line_ids)
+
+        for line_item in lines:
+            if not line_item.part:
+                continue
+
+            if line_item.part.virtual:
+                continue
+
+            unallocated = line_item.quantity - line_item.allocated_quantity()
+
+            if unallocated <= 0:
+                continue
+
+            available_stock = stock.models.StockItem.objects.filter(
+                stock.models.StockItem.IN_STOCK_FILTER, part=line_item.part
+            )
+
+            if location:
+                sublocations = location.get_descendants(include_self=True)
+                available_stock = available_stock.filter(
+                    location__in=list(sublocations)
+                )
+
+            if exclude_location:
+                sublocations = exclude_location.get_descendants(include_self=True)
+                available_stock = available_stock.exclude(
+                    location__in=list(sublocations)
+                )
+
+            if serialized_stock == 'serialized':
+                available_stock = available_stock.filter(
+                    serial__isnull=False, quantity=1
+                ).exclude(serial='')
+            elif serialized_stock == 'unserialized':
+                available_stock = available_stock.filter(
+                    Q(serial__isnull=True) | Q(serial='')
+                )
+
+            # Handle NULL expiry_date last when sorting by expiry.
+            if stock_sort_by == stock.models.StockSortOrder.EXPIRY_SOONEST:
+                available_stock = available_stock.order_by(
+                    F('expiry_date').asc(nulls_last=True)
+                )
+            else:
+                available_stock = available_stock.order_by(stock_sort_by)
+
+            stock_count = available_stock.count()
+
+            if stock_count == 0:
+                continue
+
+            if not interchangeable and stock_count > 1:
+                # Only allocate when a single item can fully cover the requirement.
+                single = next(
+                    (
+                        s
+                        for s in available_stock
+                        if s.unallocated_quantity() >= unallocated
+                    ),
+                    None,
+                )
+                if single is None:
+                    continue
+                available_stock = [single]
+
+            for stock_item in available_stock:
+                available_qty = stock_item.unallocated_quantity()
+
+                if available_qty <= 0:
+                    continue
+
+                quantity = min(unallocated, available_qty)
+
+                new_allocations.append(
+                    SalesOrderAllocation(
+                        line=line_item,
+                        item=stock_item,
+                        quantity=quantity,
+                        shipment=shipment,
+                    )
+                )
+
+                unallocated -= quantity
+
+                if unallocated <= 0:
+                    break
+
+        SalesOrderAllocation.objects.bulk_create(new_allocations, batch_size=250)
+
     def is_completed(self) -> bool:
         """Check if this order is "shipped" (all line items delivered).
 

src/backend/InvenTree/order/serializers.py

@@ -1990,6 +1990,113 @@ class SalesOrderShipmentAllocationSerializer(serializers.Serializer):
                 allocation.save()
 
 
+class SalesOrderAutoAllocationSerializer(serializers.Serializer):
+    """DRF serializer for auto-allocating stock items against a SalesOrder."""
+
+    class Meta:
+        """Serializer metaclass."""
+
+        fields = [
+            'location',
+            'exclude_location',
+            'shipment',
+            'interchangeable',
+            'stock_sort_by',
+            'serialized_stock',
+            'line_items',
+        ]
+
+    location = serializers.PrimaryKeyRelatedField(
+        queryset=stock.models.StockLocation.objects.all(),
+        many=False,
+        allow_null=True,
+        required=False,
+        label=_('Source Location'),
+        help_text=_(
+            'Stock location where items are sourced (leave blank to use any location)'
+        ),
+    )
+
+    exclude_location = serializers.PrimaryKeyRelatedField(
+        queryset=stock.models.StockLocation.objects.all(),
+        many=False,
+        allow_null=True,
+        required=False,
+        label=_('Exclude Location'),
+        help_text=_('Exclude stock items from this location'),
+    )
+
+    shipment = serializers.PrimaryKeyRelatedField(
+        queryset=order.models.SalesOrderShipment.objects.all(),
+        many=False,
+        allow_null=True,
+        required=False,
+        label=_('Shipment'),
+        help_text=_('Assign allocations to this shipment'),
+    )
+
+    interchangeable = serializers.BooleanField(
+        default=True,
+        label=_('Interchangeable Stock'),
+        help_text=_(
+            'Allow stock to be taken from multiple locations to fulfil a single line item'
+        ),
+    )
+
+    stock_sort_by = serializers.ChoiceField(
+        default=stock.models.STOCK_SORT_DEFAULT,
+        choices=stock.models.STOCK_SORT_CHOICES,
+        label=_('Stock Priority'),
+        help_text=_('Preferred order in which matching stock items are consumed'),
+    )
+
+    serialized_stock = serializers.ChoiceField(
+        default=order.models.SERIALIZED_STOCK_DEFAULT,
+        choices=order.models.SERIALIZED_STOCK_CHOICES,
+        label=_('Serialized Stock'),
+        help_text=_(
+            'Control whether serialized stock items are included in auto-allocation'
+        ),
+    )
+
+    line_items = serializers.PrimaryKeyRelatedField(
+        queryset=order.models.SalesOrderLineItem.objects.all(),
+        many=True,
+        required=False,
+        default=list,
+        label=_('Line Items'),
+        help_text=_(
+            'Limit allocation to these line items (leave blank to allocate all lines)'
+        ),
+    )
+
+    def validate_shipment(self, shipment):
+        """Validate that the shipment belongs to this order and is not yet shipped."""
+        order_obj = self.context.get('order')
+
+        if shipment is None:
+            return shipment
+
+        if shipment.shipment_date is not None:
+            raise ValidationError(_('Shipment has already been shipped'))
+
+        if order_obj and shipment.order != order_obj:
+            raise ValidationError(_('Shipment is not associated with this order'))
+
+        return shipment
+
+    def validate_line_items(self, line_items):
+        """Validate that all provided line items belong to this order."""
+        order_obj = self.context.get('order')
+
+        if order_obj and line_items:
+            for line in line_items:
+                if line.order != order_obj:
+                    raise ValidationError(_('Line item does not belong to this order'))
+
+        return line_items
+
+
 @register_importer()
 class SalesOrderExtraLineSerializer(
     AbstractExtraLineSerializer, InvenTreeModelSerializer

src/backend/InvenTree/order/tasks.py

@@ -14,6 +14,7 @@ from opentelemetry import trace
 import common.notifications
 import InvenTree.helpers_model
 import order.models
+import stock.models as stock_models
 from InvenTree.tasks import ScheduledTask, scheduled_task
 from order.events import PurchaseOrderEvents, SalesOrderEvents
 from order.status_codes import (
@@ -273,3 +274,38 @@ def complete_sales_order_shipment(
 
     # Trigger event signalling that the shipment has been completed
     trigger_event(SalesOrderEvents.SHIPMENT_COMPLETE, id=shipment.pk)
+
+
+@tracer.start_as_current_span('auto_allocate_sales_order')
+def auto_allocate_sales_order(
+    order_id: int,
+    location_id: Optional[int] = None,
+    exclude_location_id: Optional[int] = None,
+    shipment_id: Optional[int] = None,
+    line_ids: Optional[list] = None,
+    **kwargs,
+):
+    """Run auto-allocation for a specified SalesOrder."""
+    sales_order = order.models.SalesOrder.objects.get(pk=order_id)
+
+    location = (
+        stock_models.StockLocation.objects.get(pk=location_id) if location_id else None
+    )
+    exclude_location = (
+        stock_models.StockLocation.objects.get(pk=exclude_location_id)
+        if exclude_location_id
+        else None
+    )
+    shipment = (
+        order.models.SalesOrderShipment.objects.get(pk=shipment_id)
+        if shipment_id
+        else None
+    )
+
+    sales_order.auto_allocate_stock(
+        location=location,
+        exclude_location=exclude_location,
+        shipment=shipment,
+        line_ids=line_ids or None,
+        **kwargs,
+    )

src/backend/InvenTree/order/test_api.py

@@ -21,6 +21,7 @@ from common.settings import set_global_setting
 from company.models import Company, SupplierPart, SupplierPriceBreak
 from InvenTree.unit_test import InvenTreeAPITestCase
 from order import models
+from order.models import SalesOrderAllocation, SalesOrderLineItem, SalesOrderShipment
 from order.status_codes import (
     PurchaseOrderStatus,
     ReturnOrderLineStatus,
@@ -31,7 +32,7 @@ from order.status_codes import (
     TransferOrderStatusGroups,
 )
 from part.models import Part
-from stock.models import StockItem, StockLocation
+from stock.models import StockItem, StockLocation, StockSortOrder
 from stock.status_codes import StockStatus
 from users.models import Owner
 
@@ -3740,3 +3741,377 @@ class TransferOrderAllocateTest(OrderTest):
             ['part_detail', 'item_detail', 'order_detail', 'location_detail'],
             assert_subset=True,
         )
+
+
+class SalesOrderAutoAllocateAPITest(InvenTreeAPITestCase):
+    """API integration tests for the SalesOrder auto-allocate endpoint."""
+
+    fixtures = ['company', 'users']
+
+    roles = ['sales_order.add', 'sales_order.change', 'sales_order.delete']
+
+    @classmethod
+    def setUpTestData(cls):
+        """Create shared order, parts, locations and stock for all tests."""
+        super().setUpTestData()
+
+        cls.customer = Company.objects.create(
+            name='Test Customer', is_customer=True, description=''
+        )
+        cls.part = Part.objects.create(
+            name='AutoAlloc Part', salable=True, description=''
+        )
+
+        cls.loc_a = StockLocation.objects.create(name='Shelf A')
+        cls.loc_b = StockLocation.objects.create(name='Shelf B')
+
+    def _make_order(self, qty=50):
+        """Create a fresh SalesOrder with one line item and one shipment."""
+        order = models.SalesOrder.objects.create(
+            customer=self.customer,
+            reference=f'SO-TEST-{models.SalesOrder.objects.count()}',
+        )
+        line = SalesOrderLineItem.objects.create(
+            order=order, part=self.part, quantity=qty
+        )
+        shipment = SalesOrderShipment.objects.create(order=order)
+        return order, line, shipment
+
+    def _url(self, pk):
+        return reverse('api-so-auto-allocate', kwargs={'pk': pk})
+
+    # ------------------------------------------------------------------
+    # Permission and basic response tests
+    # ------------------------------------------------------------------
+
+    def test_requires_authentication(self):
+        """POST without authentication returns 401."""
+        self.client.logout()
+        order, _, _ = self._make_order()
+        self.post(self._url(order.pk), {}, expected_code=401)
+
+    def test_basic_post_returns_200(self):
+        """POST with defaults runs synchronously in tests and returns 200."""
+        order, line, _ = self._make_order()
+        StockItem.objects.create(part=self.part, quantity=100)
+
+        response = self.post(self._url(order.pk), {}, expected_code=200)
+
+        self.assertIn('task_id', response.data)
+        self.assertTrue(response.data['complete'])
+        self.assertTrue(response.data['success'])
+
+        # Task ran synchronously — allocations are already committed
+        self.assertTrue(line.is_fully_allocated())
+
+    def test_invalid_order_pk_returns_404(self):
+        """POST to a non-existent order pk returns 404."""
+        self.post(self._url(999999), {}, expected_code=404)
+
+    # ------------------------------------------------------------------
+    # Field validation
+    # ------------------------------------------------------------------
+
+    def test_invalid_stock_sort_by_rejected(self):
+        """An unrecognised stock_sort_by value is rejected with 400."""
+        order, _, _ = self._make_order()
+        self.post(
+            self._url(order.pk),
+            {'stock_sort_by': 'not_a_valid_sort'},
+            expected_code=400,
+        )
+
+    def test_invalid_serialized_stock_rejected(self):
+        """An unrecognised serialized_stock value is rejected with 400."""
+        order, _, _ = self._make_order()
+        self.post(self._url(order.pk), {'serialized_stock': 'maybe'}, expected_code=400)
+
+    def test_shipment_from_another_order_rejected(self):
+        """A shipment that belongs to a different order is rejected with 400."""
+        order, _, _ = self._make_order()
+        _other_order, _, other_shipment = self._make_order()
+
+        self.post(
+            self._url(order.pk), {'shipment': other_shipment.pk}, expected_code=400
+        )
+
+    def test_shipped_shipment_rejected(self):
+        """A shipment that has already been marked as shipped is rejected with 400."""
+        from datetime import date
+
+        order, _, shipment = self._make_order()
+        shipment.shipment_date = date.today()
+        shipment.save()
+
+        self.post(self._url(order.pk), {'shipment': shipment.pk}, expected_code=400)
+
+    def test_line_items_from_another_order_rejected(self):
+        """line_items belonging to a different order are rejected with 400."""
+        order, _, _ = self._make_order()
+        _, other_line, _ = self._make_order()
+
+        self.post(
+            self._url(order.pk), {'line_items': [other_line.pk]}, expected_code=400
+        )
+
+    # ------------------------------------------------------------------
+    # Allocation behaviour
+    # ------------------------------------------------------------------
+
+    def test_allocates_available_stock(self):
+        """Stock is allocated to the line item after a successful POST."""
+        order, line, _ = self._make_order(qty=30)
+        item = StockItem.objects.create(part=self.part, quantity=100)
+
+        self.post(self._url(order.pk), {}, expected_code=200)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().item, item)
+        self.assertEqual(allocs.first().quantity, 30)
+
+    def test_line_items_subset_only_allocates_selected_lines(self):
+        """When line_items is specified only those lines are allocated."""
+        order = models.SalesOrder.objects.create(
+            customer=self.customer,
+            reference=f'SO-SUBSET-{models.SalesOrder.objects.count()}',
+        )
+        line_a = SalesOrderLineItem.objects.create(
+            order=order, part=self.part, quantity=10
+        )
+        part_b = Part.objects.create(name='Part B', salable=True, description='')
+        line_b = SalesOrderLineItem.objects.create(
+            order=order, part=part_b, quantity=10
+        )
+
+        StockItem.objects.create(part=self.part, quantity=50)
+        StockItem.objects.create(part=part_b, quantity=50)
+
+        self.post(self._url(order.pk), {'line_items': [line_a.pk]}, expected_code=200)
+
+        self.assertTrue(line_a.is_fully_allocated())
+        self.assertFalse(line_b.is_fully_allocated())
+
+    def test_serialized_stock_only(self):
+        """serialized_stock='serialized' allocates only serialized items."""
+        order, line, _ = self._make_order(qty=1)
+        # Unserialized item
+        StockItem.objects.create(part=self.part, quantity=50)
+        # Serialized item
+        serial_item = StockItem.objects.create(
+            part=self.part, quantity=1, serial='SN-001'
+        )
+
+        self.post(
+            self._url(order.pk), {'serialized_stock': 'serialized'}, expected_code=200
+        )
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().item, serial_item)
+
+    def test_unserialized_stock_only(self):
+        """serialized_stock='unserialized' skips serialized items."""
+        order, line, _ = self._make_order(qty=10)
+        # Serialized items only
+        for sn in range(10):
+            StockItem.objects.create(part=self.part, quantity=1, serial=f'SN-{sn}')
+
+        self.post(
+            self._url(order.pk), {'serialized_stock': 'unserialized'}, expected_code=200
+        )
+
+        self.assertFalse(line.is_fully_allocated())
+        self.assertEqual(SalesOrderAllocation.objects.filter(line=line).count(), 0)
+
+    def test_stock_sort_by_quantity_asc(self):
+        """stock_sort_by=QUANTITY_ASC consumes the smallest lot first."""
+        order, line, _ = self._make_order(qty=15)
+        small = StockItem.objects.create(part=self.part, quantity=5)
+        StockItem.objects.create(part=self.part, quantity=100)
+
+        self.post(
+            self._url(order.pk),
+            {
+                'stock_sort_by': str(StockSortOrder.QUANTITY_ASC),
+                'interchangeable': True,
+            },
+            expected_code=200,
+        )
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(any(a.item == small and a.quantity == 5 for a in allocs))
+
+    def test_stock_sort_by_quantity_desc(self):
+        """stock_sort_by=QUANTITY_DESC consumes the largest lot first, covering the requirement in one allocation."""
+        order, line, _ = self._make_order(qty=15)
+        StockItem.objects.create(part=self.part, quantity=5)
+        StockItem.objects.create(part=self.part, quantity=100)
+
+        self.post(
+            self._url(order.pk),
+            {
+                'stock_sort_by': str(StockSortOrder.QUANTITY_DESC),
+                'interchangeable': True,
+            },
+            expected_code=200,
+        )
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().quantity, 15)
+
+    def test_location_filter(self):
+        """Only stock within the specified location is used."""
+        order, line, _ = self._make_order(qty=10)
+        StockItem.objects.create(part=self.part, quantity=50, location=self.loc_a)
+        StockItem.objects.create(part=self.part, quantity=50, location=self.loc_b)
+
+        self.post(self._url(order.pk), {'location': self.loc_a.pk}, expected_code=200)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().item.location, self.loc_a)
+
+    def test_exclude_location_filter(self):
+        """Stock in the excluded location is not used."""
+        order, line, _ = self._make_order(qty=10)
+        StockItem.objects.create(part=self.part, quantity=50, location=self.loc_a)
+        StockItem.objects.create(part=self.part, quantity=50, location=self.loc_b)
+
+        self.post(
+            self._url(order.pk), {'exclude_location': self.loc_a.pk}, expected_code=200
+        )
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().item.location, self.loc_b)
+
+    def test_shipment_assigned_to_allocations(self):
+        """When a shipment is specified, all allocations are assigned to it."""
+        order, line, shipment = self._make_order(qty=20)
+        StockItem.objects.create(part=self.part, quantity=100)
+
+        self.post(self._url(order.pk), {'shipment': shipment.pk}, expected_code=200)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        for alloc in allocs:
+            self.assertEqual(alloc.shipment, shipment)
+
+    def test_interchangeable_false_skips_split_stock(self):
+        """With interchangeable=False, allocation is skipped when no single item covers the full quantity."""
+        order, line, _ = self._make_order(qty=50)
+        StockItem.objects.create(part=self.part, quantity=20)
+        StockItem.objects.create(part=self.part, quantity=20)
+
+        self.post(self._url(order.pk), {'interchangeable': False}, expected_code=200)
+
+        self.assertFalse(line.is_fully_allocated())
+        self.assertEqual(SalesOrderAllocation.objects.filter(line=line).count(), 0)
+
+
+class SalesOrderAllocationBulkDeleteAPITest(InvenTreeAPITestCase):
+    """API integration tests for bulk-delete of SalesOrderAllocation, verifying shipped allocations are protected."""
+
+    fixtures = ['company', 'users']
+
+    roles = ['sales_order.add', 'sales_order.change', 'sales_order.delete']
+
+    @classmethod
+    def setUpTestData(cls):
+        """Create shared order, part and stock for all tests."""
+        super().setUpTestData()
+
+        cls.customer = models.Company.objects.create(
+            name='BulkDelete Customer', is_customer=True, description=''
+        )
+        cls.part = Part.objects.create(
+            name='BulkDelete Part', salable=True, description=''
+        )
+
+    def _make_order_with_allocations(self, n_unshipped=2, n_shipped=1):
+        """Return (order, unshipped_allocations, shipped_allocations)."""
+        order = models.SalesOrder.objects.create(
+            customer=self.customer,
+            reference=f'SO-BD-{models.SalesOrder.objects.count()}',
+        )
+        line = SalesOrderLineItem.objects.create(
+            order=order, part=self.part, quantity=100
+        )
+        unshipped_shipment = models.SalesOrderShipment.objects.create(
+            order=order, reference='1'
+        )
+
+        shipped_shipment = models.SalesOrderShipment.objects.create(
+            order=order, reference='2'
+        )
+        shipped_shipment.shipment_date = date.today()
+        shipped_shipment.save()
+
+        unshipped = []
+        for _ in range(n_unshipped):
+            item = StockItem.objects.create(part=self.part, quantity=10)
+            alloc = SalesOrderAllocation.objects.create(
+                line=line, item=item, quantity=10, shipment=unshipped_shipment
+            )
+            unshipped.append(alloc)
+
+        shipped = []
+        for _ in range(n_shipped):
+            item = StockItem.objects.create(part=self.part, quantity=10)
+            alloc = SalesOrderAllocation.objects.create(
+                line=line, item=item, quantity=10, shipment=shipped_shipment
+            )
+            shipped.append(alloc)
+
+        return order, unshipped, shipped
+
+    def _url(self):
+        return reverse('api-so-allocation-list')
+
+    # ------------------------------------------------------------------
+    # Basic bulk-delete
+    # ------------------------------------------------------------------
+
+    def test_bulk_delete_unshipped_allocations(self):
+        """Unshipped allocations can be bulk-deleted."""
+        _, unshipped, _ = self._make_order_with_allocations(n_unshipped=2, n_shipped=0)
+        ids = [a.pk for a in unshipped]
+
+        self.delete(self._url(), {'items': ids}, expected_code=200)
+
+        self.assertFalse(SalesOrderAllocation.objects.filter(pk__in=ids).exists())
+
+    # ------------------------------------------------------------------
+    # Shipped allocation protection
+    # ------------------------------------------------------------------
+
+    def test_shipped_allocations_are_not_deleted(self):
+        """Shipped allocations are silently skipped when included in a bulk-delete request."""
+        _, _, shipped = self._make_order_with_allocations(n_unshipped=0, n_shipped=2)
+        ids = [a.pk for a in shipped]
+
+        self.delete(self._url(), {'items': ids}, expected_code=200)
+
+        # All shipped allocations should still exist
+        self.assertEqual(SalesOrderAllocation.objects.filter(pk__in=ids).count(), 2)
+
+    def test_mixed_delete_removes_only_unshipped(self):
+        """A bulk-delete of mixed shipped/unshipped allocations removes only the unshipped ones."""
+        _, unshipped, shipped = self._make_order_with_allocations(
+            n_unshipped=2, n_shipped=2
+        )
+        all_ids = [a.pk for a in unshipped] + [a.pk for a in shipped]
+
+        self.delete(self._url(), {'items': all_ids}, expected_code=200)
+
+        # Unshipped should be gone
+        for alloc in unshipped:
+            self.assertFalse(SalesOrderAllocation.objects.filter(pk=alloc.pk).exists())
+
+        # Shipped should remain
+        shipped_ids = [a.pk for a in shipped]
+        self.assertEqual(
+            SalesOrderAllocation.objects.filter(pk__in=shipped_ids).count(), 2
+        )

src/backend/InvenTree/order/test_sales_order.py

@@ -5,6 +5,7 @@ from datetime import datetime, timedelta
 from django.contrib.auth import get_user_model
 from django.contrib.auth.models import Group
 from django.core.exceptions import ValidationError
+from django.db.models import Sum
 
 import order.tasks
 from common.models import InvenTreeSetting, NotificationMessage
@@ -20,7 +21,7 @@ from order.models import (
     SalesOrderShipment,
 )
 from part.models import Part
-from stock.models import StockItem
+from stock.models import StockItem, StockLocation
 from users.models import Owner
 
 
@@ -619,3 +620,231 @@ class SalesOrderTest(InvenTreeTestCase):
         # Ensure that virtual line item quantity values have been updated
         for line in so.lines.all():
             self.assertEqual(line.shipped, line.quantity)
+
+
+class SalesOrderAutoAllocateTest(InvenTreeTestCase):
+    """Tests for SalesOrder.auto_allocate_stock()."""
+
+    fixtures = ['company', 'users']
+
+    @classmethod
+    def setUpTestData(cls):
+        """Create a basic order, line items, and stock items for each test."""
+        cls.customer = Company.objects.create(
+            name='Auto Alloc Co', description='', is_customer=True
+        )
+        cls.part = Part.objects.create(
+            name='Widget', salable=True, description='A salable widget'
+        )
+        cls.virtual_part = Part.objects.create(
+            name='Virtual Widget',
+            salable=True,
+            virtual=True,
+            description='A virtual part',
+        )
+
+        cls.loc_a = StockLocation.objects.create(name='Shelf A')
+        cls.loc_b = StockLocation.objects.create(name='Shelf B', parent=cls.loc_a)
+
+    def _make_order(self, qty=50):
+        order = SalesOrder.objects.create(customer=self.customer)
+        line = SalesOrderLineItem.objects.create(
+            order=order, part=self.part, quantity=qty
+        )
+        shipment = SalesOrderShipment.objects.create(order=order)
+        return order, line, shipment
+
+    def test_allocates_single_item(self):
+        """A single stock item that covers the full quantity is fully allocated."""
+        order, line, _ = self._make_order(qty=30)
+        stock = StockItem.objects.create(part=self.part, quantity=100)
+
+        order.auto_allocate_stock()
+
+        self.assertEqual(SalesOrderAllocation.objects.filter(line=line).count(), 1)
+        alloc = SalesOrderAllocation.objects.get(line=line)
+        self.assertEqual(alloc.item, stock)
+        self.assertEqual(alloc.quantity, 30)
+        self.assertTrue(line.is_fully_allocated())
+
+    def test_interchangeable_consumes_multiple_items(self):
+        """With interchangeable=True (default), multiple stock items are consumed."""
+        order, line, _ = self._make_order(qty=50)
+        StockItem.objects.create(part=self.part, quantity=20)
+        StockItem.objects.create(part=self.part, quantity=40)
+
+        order.auto_allocate_stock(interchangeable=True)
+
+        total = SalesOrderAllocation.objects.filter(line=line).aggregate(
+            t=Sum('quantity')
+        )['t']
+        self.assertEqual(total, 50)
+        self.assertTrue(line.is_fully_allocated())
+
+    def test_not_interchangeable_skips_split_stock(self):
+        """With interchangeable=False, allocation is skipped when stock is split."""
+        order, line, _ = self._make_order(qty=50)
+        StockItem.objects.create(part=self.part, quantity=20)
+        StockItem.objects.create(part=self.part, quantity=20)
+
+        order.auto_allocate_stock(interchangeable=False)
+
+        self.assertEqual(SalesOrderAllocation.objects.filter(line=line).count(), 0)
+        self.assertFalse(line.is_fully_allocated())
+
+    def test_not_interchangeable_uses_single_sufficient_item(self):
+        """With interchangeable=False, a single item that covers the full qty is used."""
+        order, line, _ = self._make_order(qty=30)
+        StockItem.objects.create(part=self.part, quantity=10)
+        StockItem.objects.create(part=self.part, quantity=50)
+
+        order.auto_allocate_stock(interchangeable=False)
+
+        self.assertEqual(SalesOrderAllocation.objects.filter(line=line).count(), 1)
+        alloc = SalesOrderAllocation.objects.get(line=line)
+        self.assertEqual(alloc.quantity, 30)
+
+    def test_location_filter(self):
+        """Only stock within the specified location tree is considered."""
+        order, line, _ = self._make_order(qty=10)
+        StockItem.objects.create(part=self.part, quantity=100, location=self.loc_a)
+        StockItem.objects.create(part=self.part, quantity=100)  # no location
+
+        order.auto_allocate_stock(location=self.loc_a)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        for alloc in allocs:
+            self.assertEqual(alloc.item.location, self.loc_a)
+
+    def test_exclude_location_filter(self):
+        """Stock within the excluded location tree is not used."""
+        order, line, _ = self._make_order(qty=10)
+        excluded = StockItem.objects.create(
+            part=self.part, quantity=100, location=self.loc_a
+        )
+        included = StockItem.objects.create(part=self.part, quantity=100)
+
+        order.auto_allocate_stock(exclude_location=self.loc_a)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        allocated_items = [a.item for a in allocs]
+        self.assertNotIn(excluded, allocated_items)
+        self.assertIn(included, allocated_items)
+
+    def test_skips_fully_allocated_lines(self):
+        """Lines that are already fully allocated are not touched."""
+        order, line, shipment = self._make_order(qty=10)
+        existing = StockItem.objects.create(part=self.part, quantity=100)
+        SalesOrderAllocation.objects.create(
+            line=line, item=existing, quantity=10, shipment=shipment
+        )
+        self.assertTrue(line.is_fully_allocated())
+
+        order.auto_allocate_stock()
+
+        self.assertEqual(SalesOrderAllocation.objects.filter(line=line).count(), 1)
+
+    def test_skips_virtual_parts(self):
+        """Line items for virtual parts are skipped (virtual parts cannot hold stock)."""
+        order = SalesOrder.objects.create(customer=self.customer)
+        virtual_line = SalesOrderLineItem.objects.create(
+            order=order, part=self.virtual_part, quantity=5
+        )
+
+        order.auto_allocate_stock()
+
+        self.assertEqual(
+            SalesOrderAllocation.objects.filter(line=virtual_line).count(), 0
+        )
+        # Virtual parts are considered fully allocated without any stock
+        self.assertTrue(virtual_line.is_fully_allocated())
+
+    def test_allocates_serialized_stock(self):
+        """Serialized stock items are included in auto-allocation."""
+        order, line, _ = self._make_order(qty=1)
+        serialized = StockItem.objects.create(
+            part=self.part, quantity=1, serial='SN001'
+        )
+
+        order.auto_allocate_stock()
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().item, serialized)
+        self.assertTrue(line.is_fully_allocated())
+
+    def test_shipment_assigned(self):
+        """Allocations are assigned to the provided shipment."""
+        order, line, shipment = self._make_order(qty=10)
+        StockItem.objects.create(part=self.part, quantity=50)
+
+        order.auto_allocate_stock(shipment=shipment)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        for alloc in allocs:
+            self.assertEqual(alloc.shipment, shipment)
+
+    def test_sort_quantity_asc(self):
+        """quantity_asc sort consumes smallest lots first."""
+        order, line, _ = self._make_order(qty=15)
+        small = StockItem.objects.create(part=self.part, quantity=5)
+        StockItem.objects.create(part=self.part, quantity=100)
+
+        order.auto_allocate_stock(stock_sort_by='quantity', interchangeable=True)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line).order_by('quantity')
+        self.assertTrue(allocs.exists())
+        # Small lot should be fully consumed
+        self.assertTrue(any(a.item == small and a.quantity == 5 for a in allocs))
+
+    def test_sort_quantity_desc(self):
+        """quantity_desc sort consumes largest lots first."""
+        order, line, _ = self._make_order(qty=15)
+        StockItem.objects.create(part=self.part, quantity=5)
+        large = StockItem.objects.create(part=self.part, quantity=100)
+
+        order.auto_allocate_stock(stock_sort_by='-quantity', interchangeable=True)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        # Large lot should be the first consumed (fully covers 15)
+        self.assertEqual(allocs.count(), 1)
+        self.assertEqual(allocs.first().item, large)
+
+    def test_task_resolves_pk_params(self):
+        """auto_allocate_sales_order task resolves location/shipment pks to instances."""
+        from order.tasks import auto_allocate_sales_order
+
+        order, line, shipment = self._make_order(qty=10)
+        StockItem.objects.create(part=self.part, quantity=50, location=self.loc_a)
+
+        auto_allocate_sales_order(
+            order.pk, location_id=self.loc_a.pk, shipment_id=shipment.pk
+        )
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        for alloc in allocs:
+            self.assertEqual(alloc.shipment, shipment)
+            self.assertEqual(alloc.item.location, self.loc_a)
+
+    def test_task_exclude_location_pk(self):
+        """auto_allocate_sales_order respects exclude_location_id parameter."""
+        from order.tasks import auto_allocate_sales_order
+
+        order, line, _ = self._make_order(qty=10)
+        excluded = StockItem.objects.create(
+            part=self.part, quantity=50, location=self.loc_a
+        )
+        included = StockItem.objects.create(part=self.part, quantity=50)
+
+        auto_allocate_sales_order(order.pk, exclude_location_id=self.loc_a.pk)
+
+        allocs = SalesOrderAllocation.objects.filter(line=line)
+        self.assertTrue(allocs.exists())
+        allocated_items = [a.item for a in allocs]
+        self.assertNotIn(excluded, allocated_items)
+        self.assertIn(included, allocated_items)

src/backend/InvenTree/stock/models.py

@@ -38,6 +38,7 @@ import stock.tasks
 from common.icons import validate_icon
 from common.settings import get_global_setting
 from company import models as CompanyModels
+from generic.enums import StringEnum
 from generic.states import StatusCodeMixin
 from generic.states.fields import InvenTreeCustomStatusModelField
 from InvenTree.fields import InvenTreeModelMoneyField, InvenTreeURLField
@@ -399,6 +400,27 @@ class StockItemReportContext(report.mixins.BaseReportContext):
     test_templates: dict[str, PartModels.PartTestTemplate]
 
 
+class StockSortOrder(StringEnum):
+    """Enum of ORM sort fields available for stock auto-allocation."""
+
+    DATE_OLDEST = 'updated'
+    DATE_NEWEST = '-updated'
+    QUANTITY_ASC = 'quantity'
+    QUANTITY_DESC = '-quantity'
+    EXPIRY_SOONEST = 'expiry_date'
+
+
+STOCK_SORT_CHOICES = [
+    (StockSortOrder.DATE_OLDEST, _('Oldest stock first (FIFO)')),
+    (StockSortOrder.DATE_NEWEST, _('Newest stock first (LIFO)')),
+    (StockSortOrder.QUANTITY_ASC, _('Smallest quantity first')),
+    (StockSortOrder.QUANTITY_DESC, _('Largest quantity first')),
+    (StockSortOrder.EXPIRY_SOONEST, _('Soonest expiry date first')),
+]
+
+STOCK_SORT_DEFAULT = StockSortOrder.DATE_OLDEST
+
+
 class StockItem(
     InvenTree.models.PluginValidationMixin,
     InvenTree.models.InvenTreeAttachmentMixin,

src/frontend/lib/components/Boundary.tsx

@@ -1,5 +1,5 @@
 import { t } from '@lingui/core/macro';
-import { Alert, Stack } from '@mantine/core';
+import { Alert, Stack, Text } from '@mantine/core';
 import { ErrorBoundary, type FallbackRender } from '@sentry/react';
 import { IconExclamationCircle } from '@tabler/icons-react';
 import { type ReactNode, useCallback } from 'react';
@@ -14,8 +14,12 @@ export function DefaultFallback({
       title={`INVE-E17: ${t`Error rendering component`}: ${title}`}
     >
       <Stack gap='xs'>
-        {t`An error occurred while rendering this component. Refer to the console for more information.`}
-        {t`Try reloading the page, or contact your administrator if the problem persists.`}
+        <Text size='sm'>
+          {t`An error occurred while rendering this component. Refer to the console for more information.`}
+        </Text>
+        <Text size='sm'>
+          {t`Try reloading the page, or contact your administrator if the problem persists.`}
+        </Text>
       </Stack>
     </Alert>
   );

src/frontend/lib/enums/ApiEndpoints.tsx

@@ -182,6 +182,7 @@ export enum ApiEndpoints {
   sales_order_complete = 'order/so/:id/complete/',
   sales_order_allocate = 'order/so/:id/allocate/',
   sales_order_allocate_serials = 'order/so/:id/allocate-serials/',
+  sales_order_auto_allocate = 'order/so/:id/auto-allocate/',
 
   sales_order_line_list = 'order/so-line/',
   sales_order_extra_line_list = 'order/so-extra-line/',

src/frontend/src/forms/BuildForms.tsx

@@ -239,6 +239,10 @@ export function useBuildAutoAllocateFields({
       optional_items: {
         hidden: item_type === 'tracked',
         value: item_type === 'tracked' ? false : undefined
+      },
+      stock_sort_by: {},
+      build_lines: {
+        hidden: true
       }
     };
   }, [item_type]);

src/frontend/src/forms/SalesOrderForms.tsx

@@ -584,3 +584,28 @@ export function useSalesOrderAllocationFields({
     };
   }, [orderId, shipment]);
 }
+
+export function useSalesOrderAutoAllocateFields({
+  orderId
+}: {
+  orderId: number;
+}): ApiFormFieldSet {
+  return useMemo(() => {
+    return {
+      location: {},
+      exclude_location: {},
+      interchangeable: {},
+      stock_sort_by: {},
+      serialized_stock: {},
+      shipment: {
+        filters: {
+          order: orderId,
+          shipped: false
+        }
+      },
+      line_items: {
+        hidden: true
+      }
+    };
+  }, [orderId]);
+}

src/frontend/src/tables/build/BuildLineTable.tsx

@@ -574,6 +574,9 @@ export default function BuildLineTable({
   });
 
   const [allocateTaskId, setAllocateTaskId] = useState<string>('');
+  const [autoAllocateInitialData, setAutoAllocateInitialData] = useState<
+    Record<string, any>
+  >({});
 
   useBackgroundTask({
     taskId: allocateTaskId,
@@ -584,6 +587,24 @@ export default function BuildLineTable({
     }
   });
 
+  const autoAllocatePreFormContent = useMemo(() => {
+    const n = table.selectedRecords.length;
+    if (n > 0) {
+      return (
+        <Alert color='blue' title={t`Auto Allocate Stock`}>
+          <Text>
+            {t`Auto-allocating stock for`} {n} {t`selected line item(s)`}
+          </Text>
+        </Alert>
+      );
+    }
+    return (
+      <Alert color='green' title={t`Auto Allocate Stock`}>
+        <Text>{t`Automatically allocate untracked BOM items to this build according to the selected options`}</Text>
+      </Alert>
+    );
+  }, [table.selectedRecords]);
+
   const autoAllocateStock = useCreateApiFormModal({
     url: ApiEndpoints.build_order_auto_allocate,
     pk: build.pk,
@@ -595,17 +616,18 @@ export default function BuildLineTable({
       location: build.take_from,
       interchangeable: true,
       substitutes: true,
-      optional_items: false
+      optional_items: false,
+      ...autoAllocateInitialData
     },
     successMessage: null,
     onFormSuccess: (response: any) => {
-      setAllocateTaskId(response.task_id);
+      if (response.task_id) {
+        setAllocateTaskId(response.task_id);
+      } else {
+        table.refreshTable();
+      }
     },
-    preFormContent: (
-      <Alert color='green' title={t`Auto Allocate Stock`}>
-        <Text>{t`Automatically allocate untracked BOM items to this build according to the selected options`}</Text>
-      </Alert>
-    )
+    preFormContent: autoAllocatePreFormContent
   });
 
   const allocateStock = useAllocateStockToBuildForm({
@@ -835,6 +857,9 @@ export default function BuildLineTable({
         hidden={!visible || hasOutput}
         color='blue'
         onClick={() => {
+          setAutoAllocateInitialData({
+            build_lines: table.selectedRecords.map((r) => r.pk)
+          });
           autoAllocateStock.open();
         }}
       />,

src/frontend/src/tables/sales/SalesOrderAllocationTable.tsx

@@ -377,6 +377,10 @@ export default function SalesOrderAllocationTable({
           enableFilters: !isSubTable,
           enableDownload: !isSubTable,
           enableSelection: !isSubTable,
+          enableBulkDelete:
+            !isSubTable &&
+            allowEdit &&
+            user.hasDeleteRole(UserRoles.sales_order),
           minHeight: isSubTable ? 100 : undefined,
           rowActions: rowActions,
           tableActions: isSubTable ? undefined : tableActions,

src/frontend/src/tables/sales/SalesOrderLineItemTable.tsx

@@ -1,11 +1,12 @@
 import { t } from '@lingui/core/macro';
-import { Group, Paper, Text } from '@mantine/core';
+import { Alert, Group, Paper, Text } from '@mantine/core';
 import {
   IconArrowRight,
   IconHash,
   IconShoppingCart,
   IconSquareArrowRight,
-  IconTools
+  IconTools,
+  IconWand
 } from '@tabler/icons-react';
 import type { DataTableRowExpansionProps } from 'mantine-datatable';
 import { type ReactNode, useCallback, useMemo, useState } from 'react';
@@ -35,8 +36,10 @@ import { useBuildOrderFields } from '../../forms/BuildForms';
 import {
   useAllocateToSalesOrderForm,
   useSalesOrderAllocateSerialsFields,
+  useSalesOrderAutoAllocateFields,
   useSalesOrderLineItemFields
 } from '../../forms/SalesOrderForms';
+import useBackgroundTask from '../../hooks/UseBackgroundTask';
 import {
   useCreateApiFormModal,
   useDeleteApiFormModal,
@@ -327,6 +330,52 @@ export default function SalesOrderLineItemTable({
     }
   });
 
+  const [allocateTaskId, setAllocateTaskId] = useState<string>('');
+
+  useBackgroundTask({
+    taskId: allocateTaskId,
+    message: t`Allocating stock to sales order`,
+    successMessage: t`Stock allocation complete`,
+    onSuccess: () => {
+      table.refreshTable();
+    }
+  });
+
+  const [autoAllocateInitialData, setAutoAllocateInitialData] = useState<any>(
+    {}
+  );
+
+  const autoAllocatePreFormContent = useMemo(() => {
+    const count = table.selectedRecords.length;
+    if (count > 0) {
+      return (
+        <Alert color='blue'>
+          <Text size='sm'>
+            {t`${count} line item(s) selected — only these lines will be allocated`}
+          </Text>
+        </Alert>
+      );
+    }
+    return (
+      <Alert color='green'>
+        <Text size='sm'>{t`All unallocated line items will be allocated`}</Text>
+      </Alert>
+    );
+  }, [table.selectedRecords.length]);
+
+  const autoAllocateStock = useCreateApiFormModal({
+    url: ApiEndpoints.sales_order_auto_allocate,
+    pk: orderId,
+    title: t`Auto Allocate Stock`,
+    fields: useSalesOrderAutoAllocateFields({ orderId }),
+    initialData: autoAllocateInitialData,
+    preFormContent: autoAllocatePreFormContent,
+    successMessage: null,
+    onFormSuccess: (response: any) => {
+      setAllocateTaskId(response.task_id);
+    }
+  });
+
   const [partsToOrder, setPartsToOrder] = useState<any[]>([]);
 
   const orderPartsWizard = OrderPartsWizard({
@@ -385,9 +434,28 @@ export default function SalesOrderLineItemTable({
           );
           allocateStock.open();
         }}
+      />,
+      <ActionButton
+        key='auto-allocate-stock'
+        tooltip={t`Auto Allocate Stock`}
+        icon={<IconWand />}
+        color='blue'
+        hidden={!editable || !user.hasChangeRole(UserRoles.sales_order)}
+        onClick={() => {
+          setAutoAllocateInitialData({
+            line_items: table.selectedRecords.map((r) => r.pk)
+          });
+          autoAllocateStock.open();
+        }}
       />
     ];
-  }, [user, orderId, table.hasSelectedRecords, table.selectedRecords]);
+  }, [
+    editable,
+    user,
+    orderId,
+    table.hasSelectedRecords,
+    table.selectedRecords
+  ]);
 
   const rowActions = useCallback(
     (record: any): RowAction[] => {
@@ -529,6 +597,7 @@ export default function SalesOrderLineItemTable({
       {newBuildOrder.modal}
       {allocateBySerials.modal}
       {allocateStock.modal}
+      {autoAllocateStock.modal}
       {orderPartsWizard.wizard}
       <InvenTreeTable
         url={apiUrl(ApiEndpoints.sales_order_line_list)}

src/frontend/tests/pages/pui_sales.spec.ts

@@ -128,6 +128,42 @@ test('Sales Orders - Basic Tests', async ({ browser }) => {
   await page.getByRole('button', { name: 'Issue Order' }).waitFor();
 });
 
+test('Sales Orders - Auto Allocate', async ({ browser }) => {
+  const page = await doCachedLogin(browser, { url: 'sales/sales-order/11/' });
+
+  // Duplicate the order
+  await page.getByRole('button', { name: 'action-menu-order-actions' }).click();
+  await page.getByRole('menuitem', { name: 'Duplicate' }).click();
+  await page.getByRole('button', { name: 'Submit' }).click();
+  await page.getByText('Pending').first().waitFor();
+
+  await loadTab(page, 'Line Items');
+  await page
+    .getByRole('button', { name: 'action-button-auto-allocate-' })
+    .click();
+  await page
+    .getByRole('combobox', { name: 'choice-field-stock_sort_by' })
+    .click();
+  await page.getByRole('option', { name: 'Newest stock' }).click();
+  await page.getByRole('button', { name: 'Submit' }).click();
+
+  await page.getByText('Stock allocation complete').first().waitFor();
+  await page.getByText('10 / 10').first().waitFor();
+
+  // Cancel the order (to free up the allocated stock)
+  await page.getByRole('button', { name: 'action-menu-order-actions' }).click();
+  await page.getByRole('menuitem', { name: 'Cancel' }).click();
+  await page.getByRole('button', { name: 'Submit' }).click();
+  await page.getByText('Cancelled').first().waitFor();
+
+  // Check that the allocated stock has been released
+  await page
+    .getByRole('region', { name: 'Line Items', exact: true })
+    .getByLabel('table-refresh')
+    .click();
+  await page.getByText('0 / 10').first().waitFor();
+});
+
 test('Sales Orders - Shipments', async ({ browser }) => {
   const page = await doCachedLogin(browser);