diff --git a/src/openedx_content/applets/backup_restore/zipper.py b/src/openedx_content/applets/backup_restore/zipper.py
index a1626a576..4e2a82cb3 100644
--- a/src/openedx_content/applets/backup_restore/zipper.py
+++ b/src/openedx_content/applets/backup_restore/zipper.py
@@ -820,6 +820,12 @@ def _save_container(
             entity_key = data.get("key")
             container = containers_api.create_container(
                 learning_package.id,
+                # As of Verawood, the primary identity of a container is its
+                # `container_code`.  By convention, this equals the entity's
+                # `key` (aka `entity_ref`). It's safe to assume that all "v1"
+                # archives have an identical `key` and `container_code` for each
+                # entity-container. This assumpion may not hold true v2+.
+                container_code=data.pop("key"),
                 **data,  # should this be allowed to override any of the following fields?
                 created_by=self.user_id,
                 container_cls=container_cls,
diff --git a/src/openedx_content/applets/containers/admin.py b/src/openedx_content/applets/containers/admin.py
index df2a60ecd..45784bd9c 100644
--- a/src/openedx_content/applets/containers/admin.py
+++ b/src/openedx_content/applets/containers/admin.py
@@ -89,11 +89,13 @@ class ContainerAdmin(ReadOnlyModelAdmin):
     Django admin configuration for Container
     """
 
-    list_display = ("key", "container_type_display", "published", "draft", "created")
+    list_display = ("container_code", "container_type_display", "published", "draft", "created")
     fields = [
         "pk",
         "publishable_entity",
         "learning_package",
+        "container_code",
+        "container_type_display",
         "published",
         "draft",
         "created",
@@ -101,8 +103,9 @@ class ContainerAdmin(ReadOnlyModelAdmin):
         "see_also",
         "most_recent_parent_entity_list",
     ]
+    # container_code is a model field; container_type_display is a method
     readonly_fields = fields  # type: ignore[assignment]
-    search_fields = ["publishable_entity__uuid", "publishable_entity__key"]
+    search_fields = ["publishable_entity__uuid", "publishable_entity__key", "container_code"]
     inlines = [ContainerVersionInlineForContainer]
 
     def learning_package(self, obj: Container) -> SafeText:
@@ -184,7 +187,7 @@ class ContainerVersionInlineForEntityList(admin.TabularInline):
     fields = [
         "pk",
         "version_num",
-        "container_key",
+        "container_code",
         "title",
         "created",
         "created_by",
@@ -203,8 +206,8 @@ def get_queryset(self, request):
             )
         )
 
-    def container_key(self, obj: ContainerVersion) -> SafeText:
-        return model_detail_link(obj.container, obj.container.key)
+    def container_code(self, obj: ContainerVersion) -> SafeText:
+        return model_detail_link(obj.container, obj.container.container_code)
 
 
 class EntityListRowInline(admin.TabularInline):
diff --git a/src/openedx_content/applets/containers/api.py b/src/openedx_content/applets/containers/api.py
index 9fe192ea8..db42a98ea 100644
--- a/src/openedx_content/applets/containers/api.py
+++ b/src/openedx_content/applets/containers/api.py
@@ -136,7 +136,7 @@ def parse(entities: EntityListInput) -> list[ParsedEntityReference]:
 
 def create_container(
     learning_package_id: LearningPackage.ID,
-    key: str,
+    container_code: str,
     created: datetime,
     created_by: int | None,
     *,
@@ -149,7 +149,8 @@ def create_container(
 
     Args:
         learning_package_id: The ID of the learning package that contains the container.
-        key: The key of the container.
+        container_code: A local slug identifier for the container, unique within
+            the learning package (regardless of container type).
         created: The date and time the container was created.
         created_by: The ID of the user who created the container
         container_cls: The subclass of container to create (e.g. `Unit`)
@@ -161,15 +162,20 @@ def create_container(
     assert issubclass(container_cls, Container)
     assert container_cls is not Container, "Creating plain containers is not allowed; use a subclass of Container"
     with atomic():
+        # By convention, a Container's entity_key is set to its container_code.
+        # Do not bake this assumption into other systems. We may change it at some point.
+        entity_key = container_code
         publishable_entity = publishing_api.create_publishable_entity(
             learning_package_id,
-            key,
+            entity_key,
             created,
             created_by,
             can_stand_alone=can_stand_alone,
         )
         container = container_cls.objects.create(
             publishable_entity=publishable_entity,
+            container_code=container_code,
+            learning_package_id=learning_package_id,
             container_type=container_cls.get_container_type(),
         )
     return container
@@ -339,7 +345,7 @@ def create_container_version(
 
 def create_container_and_version(
     learning_package_id: LearningPackage.ID,
-    key: str,
+    container_code: str,
     *,
     title: str,
     container_cls: type[ContainerModel],
@@ -353,7 +359,8 @@ def create_container_and_version(
 
     Args:
         learning_package_id: The learning package ID.
-        key: The key.
+        container_code: A local slug identifier for the container, unique within
+            the learning package (regardless of container type).
         title: The title of the new container.
         container_cls: The subclass of container to create (e.g. Unit)
         entities: List of the entities that will comprise the entity list, in
@@ -368,7 +375,7 @@ def create_container_and_version(
     with atomic(savepoint=False):
         container = create_container(
             learning_package_id,
-            key,
+            container_code,
             created,
             created_by,
             can_stand_alone=can_stand_alone,
diff --git a/src/openedx_content/applets/containers/models.py b/src/openedx_content/applets/containers/models.py
index ece19c799..8f9de8d23 100644
--- a/src/openedx_content/applets/containers/models.py
+++ b/src/openedx_content/applets/containers/models.py
@@ -11,8 +11,9 @@
 from django.db import models
 from typing_extensions import deprecated
 
-from openedx_django_lib.fields import case_sensitive_char_field
+from openedx_django_lib.fields import case_sensitive_char_field, code_field, code_field_check
 
+from ..publishing.models.learning_package import LearningPackage
 from ..publishing.models.publishable_entity import (
     PublishableEntity,
     PublishableEntityMixin,
@@ -171,6 +172,12 @@ class Container(PublishableEntityMixin):
     olx_tag_name: str = ""
     _type_instance: ContainerType  # Cache used by get_container_type()
 
+    # This foreign key is technically redundant because we're already locked to
+    # a single LearningPackage through our publishable_entity relation. However,
+    # having this foreign key directly allows us to make indexes that efficiently
+    # query by other Container fields within a given LearningPackage.
+    learning_package = models.ForeignKey(LearningPackage, on_delete=models.CASCADE)
+
     # The type of the container. Cannot be changed once the container is created.
     container_type = models.ForeignKey(
         ContainerType,
@@ -179,6 +186,11 @@ class Container(PublishableEntityMixin):
         editable=False,
     )
 
+    # container_code is an identifier that is local to the learning_package.
+    # Unlike component_code, it is unique across all container types within
+    # the same LearningPackage.
+    container_code = code_field()
+
     @property
     def id(self) -> ID:
         return cast(Container.ID, self.publishable_entity_id)
@@ -194,6 +206,15 @@ def pk(self):
         # override this with a deprecated marker, so it shows a warning in developer's IDEs like VS Code.
         return self.id
 
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(
+                fields=["learning_package", "container_code"],
+                name="oel_container_uniq_lp_cc",
+            ),
+            code_field_check("container_code", name="oel_container_code_regex"),
+        ]
+
     @classmethod
     def validate_entity(cls, entity: PublishableEntity) -> None:
         """
diff --git a/src/openedx_content/applets/sections/api.py b/src/openedx_content/applets/sections/api.py
index 0aee1c7bd..5449235eb 100644
--- a/src/openedx_content/applets/sections/api.py
+++ b/src/openedx_content/applets/sections/api.py
@@ -31,7 +31,7 @@ def get_section(section_id: Section.ID, /):
 
 def create_section_and_version(
     learning_package_id: LearningPackage.ID,
-    key: str,
+    container_code: str,
     *,
     title: str,
     subsections: Iterable[Subsection | SubsectionVersion] | None = None,
@@ -48,7 +48,7 @@ def create_section_and_version(
     """
     section, sv = containers_api.create_container_and_version(
         learning_package_id,
-        key=key,
+        container_code=container_code,
         title=title,
         entities=subsections,
         created=created,
diff --git a/src/openedx_content/applets/subsections/api.py b/src/openedx_content/applets/subsections/api.py
index 5d2a6cdb0..1d9544990 100644
--- a/src/openedx_content/applets/subsections/api.py
+++ b/src/openedx_content/applets/subsections/api.py
@@ -31,7 +31,7 @@ def get_subsection(subsection_id: Subsection.ID, /):
 
 def create_subsection_and_version(
     learning_package_id: LearningPackage.ID,
-    key: str,
+    container_code: str,
     *,
     title: str,
     units: Iterable[Unit | UnitVersion] | None = None,
@@ -48,7 +48,7 @@ def create_subsection_and_version(
     """
     subsection, sv = containers_api.create_container_and_version(
         learning_package_id,
-        key=key,
+        container_code=container_code,
         title=title,
         entities=units,
         created=created,
diff --git a/src/openedx_content/applets/units/api.py b/src/openedx_content/applets/units/api.py
index cde86bf0b..415ebf291 100644
--- a/src/openedx_content/applets/units/api.py
+++ b/src/openedx_content/applets/units/api.py
@@ -31,7 +31,7 @@ def get_unit(unit_id: Unit.ID, /):
 
 def create_unit_and_version(
     learning_package_id: LearningPackage.ID,
-    key: str,
+    container_code: str,
     *,
     title: str,
     components: Iterable[Component | ComponentVersion] | None = None,
@@ -48,7 +48,7 @@ def create_unit_and_version(
     """
     unit, uv = containers_api.create_container_and_version(
         learning_package_id,
-        key=key,
+        container_code=container_code,
         title=title,
         entities=components,
         created=created,
diff --git a/src/openedx_content/migrations/0010_add_container_code.py b/src/openedx_content/migrations/0010_add_container_code.py
new file mode 100644
index 000000000..4dc83cd6a
--- /dev/null
+++ b/src/openedx_content/migrations/0010_add_container_code.py
@@ -0,0 +1,97 @@
+import re
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+import openedx_django_lib.fields
+
+
+def backfill_container_code(apps, schema_editor):
+    """
+    Backfill container_code and learning_package from publishable_entity.
+
+    For existing containers, container_code is set to the entity key (the
+    only identifier available at this point). Future containers will have
+    container_code set by the caller.
+    """
+    Container = apps.get_model("openedx_content", "Container")
+    for container in Container.objects.select_related("publishable_entity__learning_package").all():
+        container.learning_package = container.publishable_entity.learning_package
+        container.container_code = container.publishable_entity.key
+        container.save(update_fields=["learning_package", "container_code"])
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("openedx_content", "0009_rename_component_local_key_to_component_code"),
+    ]
+
+    operations = [
+        # 1. Add learning_package FK (nullable initially for backfill)
+        migrations.AddField(
+            model_name="container",
+            name="learning_package",
+            field=models.ForeignKey(
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                to="openedx_content.learningpackage",
+            ),
+        ),
+        # 2. Add container_code (nullable initially for backfill)
+        migrations.AddField(
+            model_name="container",
+            name="container_code",
+            field=openedx_django_lib.fields.MultiCollationCharField(
+                db_collations={"mysql": "utf8mb4_bin", "sqlite": "BINARY"},
+                max_length=255,
+                null=True,
+            ),
+        ),
+        # 3. Backfill both fields from publishable_entity
+        migrations.RunPython(backfill_container_code, migrations.RunPython.noop),
+        # 4. Make both fields non-nullable and add regex validation to container_code
+        migrations.AlterField(
+            model_name="container",
+            name="learning_package",
+            field=models.ForeignKey(
+                null=False,
+                on_delete=django.db.models.deletion.CASCADE,
+                to="openedx_content.learningpackage",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="container",
+            name="container_code",
+            field=openedx_django_lib.fields.MultiCollationCharField(
+                db_collations={"mysql": "utf8mb4_bin", "sqlite": "BINARY"},
+                max_length=255,
+                validators=[
+                    django.core.validators.RegexValidator(
+                        re.compile(r"^[a-zA-Z0-9_.-]+\Z"),
+                        "Enter a valid \"code name\" consisting of letters, numbers, "
+                        "underscores, hyphens, or periods.",
+                        "invalid",
+                    ),
+                ],
+            ),
+        ),
+        # 5. Add uniqueness constraint
+        migrations.AddConstraint(
+            model_name="container",
+            constraint=models.UniqueConstraint(
+                fields=["learning_package", "container_code"],
+                name="oel_container_uniq_lp_cc",
+            ),
+        ),
+        # 6. Add db-level regex validation
+        migrations.AddConstraint(
+            model_name='container',
+            constraint=models.CheckConstraint(
+                condition=django.db.models.lookups.Regex(models.F('container_code'), '^[a-zA-Z0-9_.-]+\\Z'),
+                name='oel_container_code_regex',
+                violation_error_message='Enter a valid "code name" consisting of letters, numbers, underscores, hyphens, or periods.',
+            ),
+        ),
+    ]
diff --git a/src/openedx_core/__init__.py b/src/openedx_core/__init__.py
index c232e21a0..356ebefd6 100644
--- a/src/openedx_core/__init__.py
+++ b/src/openedx_core/__init__.py
@@ -6,4 +6,4 @@
 """
 
 # The version for the entire repository
-__version__ = "0.41.0"
+__version__ = "0.42.0"
diff --git a/tests/openedx_content/applets/backup_restore/test_backup.py b/tests/openedx_content/applets/backup_restore/test_backup.py
index 6e9dc733c..8f60ff20a 100644
--- a/tests/openedx_content/applets/backup_restore/test_backup.py
+++ b/tests/openedx_content/applets/backup_restore/test_backup.py
@@ -160,7 +160,7 @@ def setUpTestData(cls):
 
         api.create_container(
             learning_package_id=cls.learning_package.id,
-            key="unit-1",
+            container_code="unit-1",
             created=cls.now,
             created_by=cls.user.id,
             container_cls=Unit,
diff --git a/tests/openedx_content/applets/collections/test_api.py b/tests/openedx_content/applets/collections/test_api.py
index daf839cfa..8bd52a1db 100644
--- a/tests/openedx_content/applets/collections/test_api.py
+++ b/tests/openedx_content/applets/collections/test_api.py
@@ -269,7 +269,7 @@ def setUpTestData(cls) -> None:
         created_time = datetime(2025, 4, 1, tzinfo=timezone.utc)
         cls.draft_unit = api.create_container(
             learning_package_id=cls.learning_package.id,
-            key="unit-1",
+            container_code="unit-1",
             created=created_time,
             created_by=cls.user.id,
             container_cls=Unit,
diff --git a/tests/openedx_content/applets/containers/test_api.py b/tests/openedx_content/applets/containers/test_api.py
index f40f16cd5..a902578f7 100644
--- a/tests/openedx_content/applets/containers/test_api.py
+++ b/tests/openedx_content/applets/containers/test_api.py
@@ -141,13 +141,16 @@ def _other_lp_child(lp2: LearningPackage) -> TestEntity:
 
 
 def create_test_container(
-    learning_package: LearningPackage, key: str, entities: containers_api.EntityListInput, title: str = ""
+    learning_package: LearningPackage,
+    container_code: str,
+    entities: containers_api.EntityListInput,
+    title: str = "",
 ) -> TestContainer:
     """Create a TestContainer with a draft version"""
     container, _version = containers_api.create_container_and_version(
         learning_package.id,
-        key=key,
-        title=title or f"Container ({key})",
+        container_code=container_code,
+        title=title or f"Container ({container_code})",
         entities=entities,
         container_cls=TestContainer,
         created=now,
@@ -161,7 +164,7 @@ def _parent_of_two(lp: LearningPackage, child_entity1: TestEntity, child_entity2
     """An TestContainer with two children"""
     return create_test_container(
         lp,
-        key="parent_of_two",
+        container_code="parent_of_two",
         title="Generic Container with Two Unpinned Children",
         entities=[child_entity1, child_entity2],
     )
@@ -177,7 +180,7 @@ def _parent_of_three(
     """An TestContainer with three children, two of which are pinned"""
     return create_test_container(
         lp,
-        key="parent_of_three",
+        container_code="parent_of_three",
         title="Generic Container with Two 📌 Pinned Children and One Unpinned",
         entities=[child_entity3.versioning.draft, child_entity2.versioning.draft, child_entity1],
     )
@@ -193,7 +196,7 @@ def _parent_of_six(
     """An TestContainer with six children, two of each entity, with different pinned combinations"""
     return create_test_container(
         lp,
-        key="parent_of_six",
+        container_code="parent_of_six",
         title="Generic Container with Two 📌 Pinned Children and One Unpinned",
         entities=[
             # 1: both unpinned, 2: both pinned, and 3: pinned and unpinned
@@ -216,7 +219,7 @@ def _grandparent(
     """An ContainerContainer with two unpinned children"""
     grandparent, _version = containers_api.create_container_and_version(
         lp.id,
-        key="grandparent",
+        container_code="grandparent",
         title="Generic Container with Two Unpinned TestContainer children",
         entities=[parent_of_two, parent_of_three],
         container_cls=ContainerContainer,
@@ -235,7 +238,7 @@ def _container_of_uninstalled_type(lp: LearningPackage, child_entity1: TestEntit
     # First create a TestContainer, then we'll modify it to simulate it being from an uninstalled plugin
     container, _ = containers_api.create_container_and_version(
         lp.id,
-        key="abandoned-container",
+        container_code="abandoned-container",
         title="Abandoned Container 1",
         entities=[child_entity1],
         container_cls=TestContainer,
@@ -252,7 +255,7 @@ def _other_lp_parent(lp2: LearningPackage, other_lp_child: TestEntity) -> TestCo
     """An TestContainer with one child"""
     other_lp_parent, _version = containers_api.create_container_and_version(
         lp2.id,
-        key="other_lp_parent",
+        container_code="other_lp_parent",
         title="Generic Container with One Unpinned Child Entity",
         entities=[other_lp_child],
         container_cls=TestContainer,
@@ -302,7 +305,7 @@ def test_create_generic_empty_container(lp: LearningPackage, admin_user) -> None
     """
     container, container_v1 = containers_api.create_container_and_version(
         lp.id,
-        key="new-container-1",
+        container_code="new-container-1",
         title="Test Container 1",
         container_cls=TestContainer,
         created=now,
@@ -356,10 +359,10 @@ def test_create_container_queries(lp: LearningPackage, child_entity1: TestEntity
     }
     # The exact numbers here aren't too important - this is just to alert us if anything significant changes.
     with django_assert_num_queries(31):
-        containers_api.create_container_and_version(lp.id, key="c1", **base_args)
+        containers_api.create_container_and_version(lp.id, container_code="c1", **base_args)
     # And try with a a container that has children:
     with django_assert_num_queries(32):
-        containers_api.create_container_and_version(lp.id, key="c2", **base_args, entities=[child_entity1])
+        containers_api.create_container_and_version(lp.id, container_code="c2", **base_args, entities=[child_entity1])
 
 
 # versioning helpers
@@ -1154,7 +1157,7 @@ def test_publishing_shared_component(lp: LearningPackage):
         lp.id,
         entities=[c1, c2, c3],
         title="Unit 1",
-        key="unit:1",
+        container_code="unit-1",
         created=now,
         created_by=None,
         container_cls=TestContainer,
@@ -1163,7 +1166,7 @@ def test_publishing_shared_component(lp: LearningPackage):
         lp.id,
         entities=[c2, c4, c5],
         title="Unit 2",
-        key="unit:2",
+        container_code="unit-2",
         created=now,
         created_by=None,
         container_cls=TestContainer,
@@ -1276,7 +1279,7 @@ def test_deep_publish_log(
     # Create a "great grandparent" container that contains "grandparent"
     great_grandparent = create_test_container(
         lp,
-        key="great_grandparent",
+        container_code="great_grandparent",
         title="Great-grandparent container",
         entities=[grandparent],
     )
@@ -1401,7 +1404,7 @@ def test_snapshots_of_published_unit(lp: LearningPackage, child_entity1: TestEnt
     child_entity1_v1 = child_entity1.versioning.draft
 
     # At first the container has one child (unpinned):
-    container = create_test_container(lp, key="c", entities=[child_entity1])
+    container = create_test_container(lp, container_code="c", entities=[child_entity1])
     modify_entity(child_entity1, title="Component 1 as of checkpoint 1")
     _, before_publish = containers_api.get_entities_in_container_as_of(container, 0)
     assert not before_publish  # Empty list
diff --git a/tests/openedx_content/applets/sections/test_api.py b/tests/openedx_content/applets/sections/test_api.py
index f4807640b..fd4b255fe 100644
--- a/tests/openedx_content/applets/sections/test_api.py
+++ b/tests/openedx_content/applets/sections/test_api.py
@@ -35,25 +35,25 @@ def setUp(self) -> None:
             "created_by": None,
         }
         self.unit_1, self.unit_1_v1 = content_api.create_unit_and_version(
-            key="unit_1",
+            container_code="unit_1",
             title="Grandchild Unit 1",
             components=[self.component_1, self.component_2],
             **common_args,
         )
         self.unit_2, self.unit_2_v1 = content_api.create_unit_and_version(
-            key="unit_2",
+            container_code="unit_2",
             title="Grandchild Unit 2",
             components=[self.component_2, self.component_1],  # Backwards order from Unit 1
             **common_args,
         )
         self.subsection_1, self.subsection_1_v1 = content_api.create_subsection_and_version(
-            key="subsection_1",
+            container_code="subsection_1",
             title="Child Subsection 1",
             units=[self.unit_1, self.unit_2],
             **common_args,
         )
         self.subsection_2, self.subsection_2_v1 = content_api.create_subsection_and_version(
-            key="subsection_2",
+            container_code="subsection_2",
             title="Child Subsection 2",
             units=[self.unit_2, self.unit_1],  # Backwards order from subsection 1
             **common_args,
@@ -64,12 +64,12 @@ def create_section_with_subsections(
         subsections: list[Subsection | SubsectionVersion],
         *,
         title="Section",
-        key="section:key",
+        container_code="section-key",
     ) -> Section:
         """Helper method to quickly create a section with some subsections"""
         section, _section_v1 = content_api.create_section_and_version(
             learning_package_id=self.learning_package.id,
-            key=key,
+            container_code=container_code,
             title=title,
             subsections=subsections,
             created=self.now,
@@ -88,7 +88,7 @@ def test_create_empty_section_and_version(self) -> None:
         """
         section, section_version = content_api.create_section_and_version(
             learning_package_id=self.learning_package.id,
-            key="section:key",
+            container_code="section-key",
             title="Section",
             created=self.now,
             created_by=None,
@@ -196,7 +196,7 @@ def test_create_section_with_invalid_children(self):
             ValidationError,
             match='The entity "unit_1" cannot be added to a "section" container.',
         ):
-            self.create_section_with_subsections([self.unit_1], key="unit:key3", title="Unit 3")
+            self.create_section_with_subsections([self.unit_1], container_code="unit-key3", title="Unit 3")
 
     def test_is_registered(self):
         assert Section in content_api.get_all_container_subclasses()
diff --git a/tests/openedx_content/applets/subsections/test_api.py b/tests/openedx_content/applets/subsections/test_api.py
index 74c7685b4..5d2378b90 100644
--- a/tests/openedx_content/applets/subsections/test_api.py
+++ b/tests/openedx_content/applets/subsections/test_api.py
@@ -30,7 +30,7 @@ def setUp(self) -> None:
         )
         self.unit_1, self.unit_1_v1 = content_api.create_unit_and_version(
             learning_package_id=self.learning_package.id,
-            key="unit1",
+            container_code="unit1",
             title="Unit 1",
             components=[self.component_1, self.component_2],
             created=self.now,
@@ -42,12 +42,12 @@ def create_subsection_with_units(
         units: list[Unit | UnitVersion],
         *,
         title="Subsection",
-        key="subsection:key",
+        container_code="subsection-key",
     ) -> Subsection:
         """Helper method to quickly create a unit with some units"""
         subsection, _subsection_v1 = content_api.create_subsection_and_version(
             learning_package_id=self.learning_package.id,
-            key=key,
+            container_code=container_code,
             title=title,
             units=units,
             created=self.now,
@@ -66,7 +66,7 @@ def test_create_empty_subsection_and_version(self):
         """
         subsection, subsection_version = content_api.create_subsection_and_version(
             learning_package_id=self.learning_package.id,
-            key="subsection:key",
+            container_code="subsection-key",
             title="Subsection",
             created=self.now,
             created_by=None,
@@ -177,7 +177,7 @@ def test_create_subsection_with_invalid_children(self):
             ValidationError,
             match='The entity "xblock.v1:problem:Query_Counting" cannot be added to a "subsection" container.',
         ):
-            self.create_subsection_with_units([self.component_1], key="unit:key3", title="Unit 3")
+            self.create_subsection_with_units([self.component_1], container_code="unit-key3", title="Unit 3")
 
     def test_is_registered(self):
         assert Subsection in content_api.get_all_container_subclasses()
diff --git a/tests/openedx_content/applets/units/test_api.py b/tests/openedx_content/applets/units/test_api.py
index 364970a8a..349ac36b2 100644
--- a/tests/openedx_content/applets/units/test_api.py
+++ b/tests/openedx_content/applets/units/test_api.py
@@ -35,12 +35,12 @@ def create_unit_with_components(
         components: list[Component | ComponentVersion],
         *,
         title="Unit",
-        key="unit:key",
+        container_code="unit-key",
     ) -> Unit:
         """Helper method to quickly create a unit with some components"""
         unit, _unit_v1 = content_api.create_unit_and_version(
             learning_package_id=self.learning_package.id,
-            key=key,
+            container_code=container_code,
             title=title,
             components=components,
             created=self.now,
@@ -59,7 +59,7 @@ def test_create_empty_unit_and_version(self):
         """
         unit, unit_version = content_api.create_unit_and_version(
             learning_package_id=self.learning_package.id,
-            key="unit:key",
+            container_code="unit-key",
             title="Unit",
             created=self.now,
             created_by=None,
@@ -120,7 +120,7 @@ def test_get_unit_other_container_type(self) -> None:
         """Test `get_unit()` when the provided ID is for a non-Unit container"""
         other_container = content_api.create_container(
             self.learning_package.id,
-            key="test",
+            container_code="test",
             created=self.now,
             created_by=None,
             container_cls=TestContainer,
@@ -153,11 +153,11 @@ def test_create_unit_with_invalid_children(self):
         # Create two units:
         unit = self.create_unit_with_components([])
         unit_version = unit.versioning.draft
-        unit2 = self.create_unit_with_components([], key="unit:key2", title="Unit 2")
+        unit2 = self.create_unit_with_components([], container_code="unit-key2", title="Unit 2")
 
         # Try adding a Unit to a Unit
         with pytest.raises(
-            ValidationError, match='The entity "unit:key2" cannot be added to a "unit" container.'
+            ValidationError, match='The entity "unit-key2" cannot be added to a "unit" container.'
         ) as err:
             content_api.create_next_unit_version(
                 unit,
@@ -187,8 +187,8 @@ def test_create_unit_with_invalid_children(self):
         assert unit.versioning.draft == unit_version
 
         # Also check that `create_unit_and_version()` has the same restriction (not just `create_next_unit_version()`)
-        with pytest.raises(ValidationError, match='The entity "unit:key2" cannot be added to a "unit" container.'):
-            self.create_unit_with_components([unit2], key="unit:key3", title="Unit 3")
+        with pytest.raises(ValidationError, match='The entity "unit-key2" cannot be added to a "unit" container.'):
+            self.create_unit_with_components([unit2], container_code="unit-key3", title="Unit 3")
 
     def test_is_registered(self):
         assert Unit in content_api.get_all_container_subclasses()