Removing a Field from an Existing NetBox Model

Removing a field touches many files. Work through the checklist below in order — remove outer consumers first (tests, docs, GraphQL, API, forms) before touching the model definition itself.

Before You Start

Determine upfront:

• Field name and which model/app owns it
• Field type: scalar, FK/M2M, GenericForeignKey, or special (JSONField, etc.)
• All references — run a broad grep before touching anything:

grep -r 'new_field\|related_thing' netbox/ --include='*.py' -l
grep -r 'new_field\|related_thing' docs/ -l

For FK/M2M fields, also check for FilterSet _id companions and GraphQL lazy annotations referencing this field.

Check dependents: if other models or code use this field (e.g. ordering, constraints, signal handlers), those references must be cleaned up too.

1. Update Tests

Update test files to remove references to the field being deleted. Specifically:

• tests/test_filtersets.py — remove test_<field> and test_<field>_id methods; remove the field from setUpTestData test objects.
• tests/test_api.py — remove the field from setUpTestData, create_data, and bulk_update_data; remove any test_list_objects_by_<field> methods.
• tests/test_views.py — remove the field from form_data, bulk_edit_data, and csv_data in setUpTestData.
• tests/test_models.py — remove any test_clean_<field> or constraint tests specific to this field.

2. Update Documentation

File: docs/models/<app>/<modelname>.md

Remove the field's entry from the ## Fields section. If the field had any cross-references in other doc pages, remove those too.

3. Update GraphQL

Filter — graphql/filters.py

Remove the filter field declaration(s) for the deleted field:

# Remove lines like:
new_field: StrFilterLookup[str] | None = strawberry_django.filter_field()

# Or for FK:
related_thing: Annotated[...] | None = strawberry_django.filter_field()
related_thing_id: ID | None = strawberry_django.filter_field()

Type — graphql/types.py

For simple fields, fields='__all__' means no change is needed — the field disappears automatically once removed from the model.

For FK fields with an explicit annotation, remove the annotation line:

# Remove:
related_thing: Annotated['RelatedThingType', strawberry.lazy('<app>.graphql.types')] | None

If the field was in an exclude list, remove it from the exclude list (it no longer exists to exclude).

4. Update the API Serializer

File: netbox/<app>/api/serializers_/<module>.py

• Simple field: remove the field name from Meta.fields (and brief_fields if present).
• FK field: remove the serializer field declaration and its name from Meta.fields:

# Remove:
related_thing = RelatedThingSerializer(nested=True, required=False, allow_null=True)
# And remove 'related_thing' from Meta.fields

5. Update Forms

There are typically up to four forms to update. Find them under netbox/<app>/forms/.

5a. Filter form — forms/filtersets.py

• Remove the field from fieldsets.
• Remove the filter field declaration (e.g. new_field = forms.CharField(...) or the DynamicModelMultipleChoiceField).

5b. Bulk edit form — forms/bulk_edit.py

• Remove the field from fieldsets and Meta.fields (if present).
• Remove the field declaration.
• Remove from nullable_fields if listed there.

5c. Bulk import form — forms/bulk_import.py

• Remove from Meta.fields.
• Remove any explicit field declaration.

5d. Model form — model_forms.py

• Remove from fieldsets.
• Remove from Meta.fields.
• Remove any explicit field declaration (e.g. a DynamicModelChoiceField).

6. Update the FilterSet

File: netbox/<app>/filtersets.py

• Simple field: remove from Meta.fields.
• FK field: remove both the <field> and <field>_id explicit filter declarations.
• search() method: if the field was included in the Q(...) chain, remove that clause.
• Remove any now-unused imports (e.g. the related model import if it was only used by this filter).

7. Update the Table

File: netbox/<app>/tables/<module>.py

• Remove the column declaration (e.g. related_thing = tables.Column(linkify=True)).
• Remove the field from Meta.fields.
• Remove from default_columns if listed there.

8. Update the Detail View Panel

File: netbox/<app>/ui/panels.py

Find the panel class for the model and remove the attribute declaration:

# Remove:
new_field = attrs.TextAttr('new_field')
related_thing = attrs.RelatedObjectAttr('related_thing', linkify=True)

If the model uses a legacy HTML template (netbox/templates/<app>/) rather than a declarative panel, remove the corresponding <tr> row from that template instead.

9. Update the SearchIndex

File: netbox/<app>/search.py

If the field was indexed for global search, remove it from the fields tuple:

# Remove:
('new_field', 300),

10. Remove the Field from the Model

File: netbox/<app>/models/<module>.py

1. Delete the field declaration.
2. If the field was in clone_fields, remove it from that tuple.
3. If clean() had validation logic specific to this field, remove those clauses. If clean() becomes empty, remove the override entirely.
4. For FK fields: remove the related_name on the target model is automatic (Django handles it). If the FK was the only reason a related model was imported, remove that import too.
5. Check Meta for references to the field:
   • ordering — if the field appears in the ordering tuple, remove it (or replace with a remaining field if ordering would otherwise become empty).
   • constraints — remove any UniqueConstraint or CheckConstraint whose fields list includes this field; if only this field remains, remove the constraint entirely; if other fields remain, remove just this field from the list.
   • indexes — remove any models.Index that includes this field.
6. For GenericForeignKey fields: if this was the only GFK, also remove the object_type ContentType FK and object_id integer field, and remove the models.Index(fields=('object_type', 'object_id')) from Meta.

11. Generate the Migration

Do NOT write migrations manually. Tell the user to run:

cd netbox/
python manage.py makemigrations <app> -n remove_<field>_from_<model> --no-header

Set DEVELOPER = True in configuration.py if the command is blocked.

Review the generated migration — it should contain only a RemoveField operation (plus any index removal for GFK fields). Apply with:

python manage.py migrate

Summary Checklist

Common Gotchas

• Work outside-in — remove tests, docs, GraphQL, and API references before touching the model, to avoid import errors during the process.
• FK fields leave no _id companion in serializers — the modern pattern uses a single field = Serializer(nested=True). Grep for the field name and the serializer class name.
• FilterSets have both <field> and <field>_id — both must be removed; they are explicit declarations, not auto-generated.
• clone_fields must be updated if the field was listed there.
• search() in filtersets — if the field was in the Q(...) chain of the search() method, that clause must be removed to avoid a FieldError at runtime.
• brief_fields in serializers — remove explicitly if the field was listed.
• makemigrations must be run, not written manually. If blocked, set DEVELOPER = True in configuration.py.
• No ruff format on existing files — use ruff check only.

References

• Panel attrs reference: netbox/netbox/ui/attrs.py
• Panel classes: netbox/<app>/ui/panels.py
• Base filterset classes: netbox/netbox/filtersets.py
• add-model-field skill: .claude/skills/add-model-field/SKILL.md (reverse of this skill)
• Contributing guide: docs/development/extending-models.md