Quathos Mailer

Suppressions

The suppression list is the memory of who you must not contact. Sending to a suppressed address is refused before it leaves the queue.

List and manage

GET /email/suppressions lists suppressions; POST adds a destination by hand, with reason MANUAL or INVALID_ADDRESS; DELETE removes one you are sure about. Hard bounces, complaints and unsubscribes add themselves automatically — and entries born from a recipient's own choice cannot be deleted through the API (removable: false).

cURL
curl -X POST https://api.qsendyx.com/api/v1/email/suppressions \
  -H "Authorization: Bearer $QUATHOS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "destination": "user@example.com", "reason": "MANUAL" }'
json
{
  "data": [
    {
      "id": "019f7155-2c40-7b11-a9d3-6e2b8f014c55",
      "destination": "user@example.com",
      "channel": "email",
      "reason": "HARD_BOUNCE",
      "detail": "550 5.1.1 mailbox unavailable",
      "removable": true,
      "created_at": "2026-07-17T18:05:36Z"
    }
  ],
  "next_cursor": null
}
A suppression carries the reason it exists.

Reasons

ReasonOrigin
HARD_BOUNCEThe recipient server rejected the address permanently.
SPAM_COMPLAINTThe recipient marked a message as spam. Not removable.
UNSUBSCRIBEThe recipient opted out of your email. Not removable.
MANUALYou added the destination yourself.
INVALID_ADDRESSYou marked the destination as invalid.
PLATFORM_BLOCKBlocked by the platform. Not removable.
Removing a suppression does not undo the reason it was added. Delete a hard-bounce entry only if you know the address is now valid — sending to dead addresses is what wrecks a sender reputation, and reputation does not roll back.