# Custom Fields Extend contact and company records with custom data fields. Store any additional information relevant to your workflow. ## List custom fields - [GET /leads/api/custom-fields](https://api.grinfi.io/openapi/custom-fields/listcustomfields.md): Retrieve all custom field definitions for contacts and companies. ## Create a custom field - [POST /leads/api/custom-fields](https://api.grinfi.io/openapi/custom-fields/createcustomfield.md): Define a new custom field for contacts or companies. ## Update a custom field - [PUT /leads/api/custom-fields/{uuid}](https://api.grinfi.io/openapi/custom-fields/updatecustomfield.md): Update a custom field's name or order. ## Delete a custom field - [DELETE /leads/api/custom-fields/{uuid}](https://api.grinfi.io/openapi/custom-fields/deletecustomfield.md): Permanently remove a custom field definition and all its values. ## Set a custom field value - [POST /leads/api/custom-field-values](https://api.grinfi.io/openapi/custom-fields/upsertcustomfieldvalue.md): Set (or update) a custom field value on a contact or company. Pass null as value to clear the field.