> For the complete documentation index, see [llms.txt](https://docs.zenlytic.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zenlytic.com/developers/api-reference/workspace-administration/attribute-definitions/create-attribute-definition.md).

# Create Attribute Definition

Create a user attribute definition in the workspace.

Returns 409 if `name` is already used by another definition in the workspace.

The `data_type` is fixed at creation time and cannot be changed afterwards.

```json
{"openapi":"3.1.0","info":{"title":"FastAPI","version":"2.0.0"},"tags":[{"name":"Attribute Definitions"}],"servers":[{"url":"https://api-external.zenlytic.com/api/v2","description":"US"},{"url":"https://euapi-external.zenlytic.com/api/v2","description":"EU"}],"security":[{"HTTPBearer":[]}],"components":{"securitySchemes":{"HTTPBearer":{"type":"http","description":"A Personal Access Token (PAT).","scheme":"bearer"}},"schemas":{"CreateUserAttributeDefinitionSchema":{"properties":{"name":{"type":"string","title":"Name","description":"A stable, unique key for this definition within the workspace, referenced by the data model - unlike `label`, it can't be changed after creation."},"data_type":{"$ref":"#/components/schemas/UserAttributeDataType","description":"Determines the format required in `value` wherever this definition is used: \"string\" allows free text, \"number\" requires a parseable number, \"date\" requires `YYYY-MM-DD`."},"label":{"type":"string","title":"Label","description":"The human-facing display text for this definition; unlike `name`, this can be changed at any time."}},"type":"object","required":["name","data_type","label"],"title":"CreateUserAttributeDefinitionSchema"},"UserAttributeDataType":{"type":"string","enum":["string","number","date"],"title":"UserAttributeDataType"},"ApiV2Response_UserAttributeDefinitionSchema_":{"properties":{"data":{"$ref":"#/components/schemas/UserAttributeDefinitionSchema"},"meta":{"$ref":"#/components/schemas/MetaSchema"}},"type":"object","required":["data","meta"],"title":"ApiV2Response[UserAttributeDefinitionSchema]"},"UserAttributeDefinitionSchema":{"properties":{"id":{"type":"string","title":"Id"},"workspace_id":{"type":"string","title":"Workspace Id"},"name":{"type":"string","title":"Name","description":"A stable, unique key for this definition within the workspace, referenced by the data model - unlike `label`, it can't be changed after creation."},"data_type":{"$ref":"#/components/schemas/UserAttributeDataType","description":"Determines the format required in `value` wherever this definition is used: \"string\" allows free text, \"number\" requires a parseable number, \"date\" requires `YYYY-MM-DD`."},"label":{"type":"string","title":"Label","description":"The human-facing display text for this definition; unlike `name`, this can be changed at any time."}},"type":"object","required":["id","workspace_id","name","data_type","label"],"title":"UserAttributeDefinitionSchema"},"MetaSchema":{"properties":{"status":{"$ref":"#/components/schemas/ResponseStatus"},"errors":{"items":{"$ref":"#/components/schemas/ErrorSchema"},"type":"array","title":"Errors","description":"Non-empty exactly when `status` is \"error\"."},"warnings":{"items":{"$ref":"#/components/schemas/WarningSchema"},"type":"array","title":"Warnings","description":"Can be non-empty even when `status` is \"success\" - a non-fatal issue with an otherwise-successful request."}},"type":"object","required":["status"],"title":"MetaSchema"},"ResponseStatus":{"type":"string","enum":["success","error"],"title":"ResponseStatus"},"ErrorSchema":{"properties":{"message":{"type":"string","title":"Message"},"status_code":{"anyOf":[{"type":"integer"},{"type":"null"}],"title":"Status Code","description":"Matches this response's actual HTTP status code."},"occurred_at":{"anyOf":[{"type":"string"},{"type":"null"}],"title":"Occurred At","description":"ISO 8601 UTC timestamp."},"error_code":{"anyOf":[{"type":"string"},{"type":"null"}],"title":"Error Code","description":"Machine-readable code for errors that need special handling (e.g. \"SSO_REQUIRED\") rather than being shown generically; null for most errors."},"error_metadata":{"anyOf":[{"$ref":"#/components/schemas/BaseErrorMetadata"},{"type":"null"}],"description":"Additional structured detail for specific error conditions; usually null."}},"type":"object","required":["message"],"title":"ErrorSchema"},"BaseErrorMetadata":{"properties":{},"type":"object","title":"BaseErrorMetadata"},"WarningSchema":{"properties":{"message":{"type":"string","title":"Message"}},"type":"object","required":["message"],"title":"WarningSchema"},"ApiV2ErrorResponse":{"properties":{"meta":{"$ref":"#/components/schemas/MetaSchema"}},"type":"object","required":["meta"],"title":"ApiV2ErrorResponse"}}},"paths":{"/workspaces/{workspace_id}/user_attribute_definitions":{"post":{"tags":["Attribute Definitions"],"summary":"Create Attribute Definition","description":"Create a user attribute definition in the workspace.\n\nReturns 409 if ``name`` is already used by another definition in the workspace.\n\nThe ``data_type`` is fixed at creation time and cannot be changed afterwards.","operationId":"create_user_attribute_definition_workspaces__workspace_id__user_attribute_definitions_post","parameters":[{"name":"workspace_id","in":"path","required":true,"schema":{"type":"string","title":"Workspace Id"}}],"requestBody":{"required":true,"content":{"application/json":{"schema":{"$ref":"#/components/schemas/CreateUserAttributeDefinitionSchema"}}}},"responses":{"201":{"description":"Successful Response","content":{"application/json":{"schema":{"$ref":"#/components/schemas/ApiV2Response_UserAttributeDefinitionSchema_"}}}},"4XX":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/ApiV2ErrorResponse"}}},"description":"Client Error"},"5XX":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/ApiV2ErrorResponse"}}},"description":"Server Error"}}}}}}
```


---

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