Create a custom field definition
Create a new custom field definition.
Required Fields:
name- Field nametype- DOCUMENT or CONTACTinputType- Input type (TEXT, NUMBER, DATE, BOOLEAN, SELECT, TEXTAREA, EMAIL, PHONE, URL, JSON)
Optional Fields:
defaultValue- Default value for the fieldrequired- Whether field is required (default: false)options- For SELECT type, the options as an array of strings, for example["Small","Large"]
Authorizations
Personal API key, e.g. Authorization: Bearer sajn_sk_.... Not scope-limited — acts as the issuing user.
Headers
API version for this request. Without it, the request uses the organization's default version; an organization without a default is pinned to the latest version by its first request.
2026-09, 2026-10 ID of the workspace this request acts in, from GET /api/v1/workspaces. Without it, an API key acts in its default workspace. The token's user must be a member of the workspace; an OAuth token only accepts the workspace it was granted for. A workspace that doesn't exist or can't be reached returns 403 WORKSPACE_ACCESS_DENIED.
Makes retries safe. A retry with the same key and the same request replays the stored response for 24 hours (header Idempotent-Replayed: true); the same key with a different request returns 400.
255Body
Body
Create custom field request
Custom field name (required)
1Field type: DOCUMENT or CONTACT (required)
DOCUMENT, CONTACT Input type (required): TEXT, NUMBER, DATE, CHECKBOX, SELECT, TEXTAREA, EMAIL, PHONE, or URL
TEXT, NUMBER, DATE, EMAIL, PHONE, URL, BOOLEAN, SELECT, JSON, TEXTAREA Default value for this field
Whether this field is required (default: false)
The options of a SELECT field, for example ["Small","Large"]. Required for SELECT.
Response
200
Unique custom field identifier
Custom field name
Field type: DOCUMENT or CONTACT
DOCUMENT, CONTACT Input type: TEXT, NUMBER, DATE, BOOLEAN, SELECT, TEXTAREA, EMAIL, PHONE, URL, or JSON
TEXT, NUMBER, DATE, EMAIL, PHONE, URL, BOOLEAN, SELECT, JSON, TEXTAREA Default value for this field
Whether this field is required
The options of a SELECT field, for example ["Small","Large"]. Null for other input types.
Date and time when custom field was created
Date and time when custom field was last updated

