Create Entity Type Field
Create a field on an entity type. Returns the schema_migration_id of the (already-completed) create migration; fetch it via Get Schema Migration to read the new field id from details.create_field.field_id.
Authentication and permissions
Token requirements: User-based token (OAuth) or Organization-scoped API key or Team-scoped API key. Send a bearer access token for one of these identities. The permissions and resource restrictions below also apply.
Authorizations
Bearer authentication header of the form Bearer <token>, where <token> is your auth token.
Body
The entity type to create the field on (required).
The unique key for the field. If omitted, derived from the name.
The display name of the field (required).
The data type of the field (required).
DATA_TYPE_UNSPECIFIED, TEXT, NUMBER, BOOL, TIMESTAMP, ENUM, ENTITY_REF, USER_REF, UNIQUE, MULTI_SELECT, FILE, TICKET_REF, TIMESTAMP_RANGE Options for ENUM / MULTI_SELECT fields (required for those data types).
Whether this field is the entity type's key (dedup identity) field.
Whether this field is the entity type's display-name field.
For ENTITY_REF fields: the single allowed target entity type. Ignored when ref_entity_type_ids is non-empty; prefer that field.
For ENTITY_REF fields: the entity types values may reference. Empty falls back to ref_entity_type_id; both empty means any type.
Response
Success
Reference to the (COMPLETED) create migration; its details.create_field.field_id is the new field id.

