API
Unassign a thread
Leave it with nobody.
DELETE/threads/{id}/assignee
Runs the real call on your workspace.
DELETE /threads/{id}/assignee
Leave it with nobody.
Example
Needs threads:write. Nobody is emailed. Answers with the assignment, which has no assignee now.
curl -X DELETE "$OE/threads/thr_7c1e4a90/assignee" -H "$AUTH"{ "object": "thread_assignment", "threadId": "thr_7c1e4a90", "assignee": null, "assignedBy": { "object": "team_member", "id": "usr_8a41be", "name": "Ada Lovelace", "email": "ada@example.com" }, "assignedAt": "2026-10-14T09:12:44.000Z", "doneBy": null, "doneAt": null}A key acts for the workspace owner. A key limited to particular addresses or domains reaches only the threads that arrived at them, and any other thread is a 404.
Google Workspace
Fastmail