# Upsert a Custom Entity instance

`UpsertCustomEntity`

`POST /api/customentities/{entityType}`

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

Insert the Custom Entity if it does not exist or update the Custom Entity with the supplied state if it does exist.

## Referenced schemas

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

[< CustomEntities](https://www.lusid.com/docs/api/lusid/endpoints/custom-entities/llms.txt)