Delete a contact

DELETE /contacts/{address}

{ "deleted": true }

404 not_found if the address is not on your list.

Their segment memberships and topic answers go with them, and any segment they were counted in is corrected.

This is almost never what you want

Deleting loses the record that they opted out. Re-import the same CSV next month and you will mail somebody who asked you not to — and the second time, they report it as spam rather than clicking unsubscribe.

POST /contacts/{address}/unsubscribe keeps the contact and the record. Use DELETE for an erasure request, or for a row that should never have existed.