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DELETE
Delete Synced Contact Field
A field’s type cannot change after it is created, and enum options cannot be removed. To change either, delete the field with this endpoint, then send the new definition in the fields of your next Upsert Synced Contact request. If your source sends field definitions with every upsert, update it to send the new definition first, or its next upsert creates the old field again. Deleting a field also deletes the values stored for it on every contact. Contacts themselves are not affected. A contact has no value for the field again until your source syncs that contact with it. To avoid that gap, define the new shape under a new key, sync contacts with values for it, then delete the old field once nothing uses it.
Only fields defined through contact upsert can be deleted. The request is rejected, and nothing is deleted, when the field:
  • is name, email, or phone_number, which returns 422
  • was created in Simple, which returns 409
  • is used by a contact segment or the call params mapping, which returns 409. Remove it from the segment or mapping first.
The endpoint also returns 401 when authentication fails, 404 when your organization has no field with that key, and 422 when the key is invalid.

Authorizations

Authorization
string
header
required

Your API key, sent as Authorization: Bearer YOUR_API_KEY

Path Parameters

fieldKey
string
required

Key of the field to delete.

Required string length: 1 - 63
Pattern: ^[a-z][a-z0-9]*(?:_[a-z0-9]+)*$

Response

The field was deleted.

key
string
required

The key of the deleted field.

deleted
boolean
required
Last modified on October 6, 2026