# Define a new Custom Entity Type.

`CreateCustomEntityType`

`POST /api/customentitytypes`

- [OpenAPI fragment](https://www.lusid.com/docs/api/lusid/endpoints/custom-entity-types/CreateCustomEntityType.json)
- [Rendered page](https://www.lusid.com/docs/api/lusid/endpoints/custom-entity-types/CreateCustomEntityType)

The API will return a Bad Request if the Custom Entity Type already exists.

## Referenced schemas

- [CreateCustomEntityTypeRequest](https://www.lusid.com/docs/api/lusid/schemas/CreateCustomEntityTypeRequest.txt)
- [CustomEntityType](https://www.lusid.com/docs/api/lusid/schemas/CustomEntityType.txt)

[< Custom Entity Types](https://www.lusid.com/docs/api/lusid/endpoints/custom-entity-types/llms.txt)