Suppressions#

The suppression list protects your sending reputation. Every send checks it per recipient, so an address that hard-bounced once is not retried into a wall.

How addresses land here#

Automatic suppression is the important one. Repeatedly mailing addresses that hard-bounce is one of the fastest ways to damage a sending domain, and it is entirely avoidable.

Add a suppression#

POST /suppressions

{ "email": "[email protected]" }

{
  "object": "suppression",
  "id": "e169aa45-1ecf-4183-9955-b1499d5701d3",
  "email": "[email protected]"
}

Adding an address that is already suppressed updates its origin rather than failing.

Add up to 100#

POST /suppressions/batch/add

{ "emails": ["[email protected]", "[email protected]"] }

{
  "object": "list",
  "data": [
    { "id": "…", "email": "[email protected]" },
    { "id": "…", "email": "[email protected]" }
  ]
}

Useful when importing a do-not-contact list from another provider — do that before your first send, not after.

Retrieve a suppression#

GET /suppressions/:suppression

Accepts an id or an email address.

{
  "id": "e169aa45-1ecf-4183-9955-b1499d5701d3",
  "email": "[email protected]",
  "origin": "bounce",
  "source_id": "4ef9a417-02e9-4d39-ad75-9611e0fcc33c",
  "created_at": "2026-10-06 23:47:56.678+00"
}

source_id is the email that caused it, for bounce and complaint origins, and null for manual entries. It answers "why is this address blocked" without guessing.

List suppressions#

GET /suppressions
GET /suppressions?origin=bounce

Always paginated. origin filters to bounce, complaint, or manual.

Remove a suppression#

DELETE /suppressions/:suppression

Accepts an id or an email.

Remove up to 100#

POST /suppressions/batch/remove

{ "emails": ["[email protected]"], "ids": ["e169aa45-…"] }

Either or both keys. Returns what was actually removed.

When to remove#

Removing a manual entry is routine — someone asked to be re-added.

Removing a bounce entry deserves a reason. If the mailbox genuinely came back (a typo'd domain now registered, a mailbox un-suspended), fine. If you are removing it because the numbers look bad, you are choosing to re-send to an address that already told you it does not exist, and receiving servers notice.

complaint entries should essentially never be removed. Someone marked your mail as spam; mailing them again is how domains get blocklisted.

Suppression and unsubscribe#

These are different mechanisms and it is worth keeping them straight:

A password reset should still reach someone who unsubscribed from marketing. It should not reach an address that does not exist. That is the distinction.

Events#

suppression.added and suppression.removed fire to subscribed webhooks.