Suppression List

Manage email addresses that are blocked from receiving emails. Addresses are automatically suppressed on permanent bounces and spam complaints, and can be managed manually via API or dashboard.

The suppression list prevents sending to email addresses that have previously hard-bounced or received spam complaints. This protects your sender reputation and improves deliverability.

Automatic suppression:

• Permanent bounces — when SES reports a permanent (hard) bounce, all bounced recipient addresses are automatically added with reason "hard_bounce"
• Spam complaints — when a recipient marks your email as spam, their address is automatically added with reason "complaint"
• Transient or undetermined bounces do NOT trigger suppression

Send behavior:

• Before every send (API and SMTP), suppressed recipients are silently filtered out
• If ALL recipients in a request are suppressed, the send fails with an error message listing the suppressed addresses
• CC and BCC recipients are also checked and filtered

Manual management:

• Add addresses manually via the dashboard or API with reason "manual"
• Remove any suppression (auto or manual) to allow sending again
• Each suppression is scoped to your workspace — other workspaces are not affected

GET/v1/suppressionsAPI Key

List all suppressed email addresses in the current workspace, ordered by most recently added.

Response

json

[
  {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "email": "bounced@example.com",
    "reason": "hard_bounce",
    "notes": "smtp; 550 5.1.1 The email account does not exist",
    "created_at": "2025-06-15T10:30:00.000Z"
  },
  {
    "id": "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
    "email": "complained@example.com",
    "reason": "complaint",
    "notes": "abuse",
    "created_at": "2025-06-14T08:15:00.000Z"
  }
]

POST/v1/suppressionsAPI Key

Manually add an email address to the suppression list. Idempotent — adding an already-suppressed address is a no-op.

Parameter	Type	In	Description
`email`required	`string`	body	Email address to suppress (will be lowercased)
`notes`	`string`	body	Optional note explaining why the address was suppressed

Request

bash

{
  "email": "user@example.com",
  "notes": "Requested removal from mailing list"
}

Response

json

{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "email": "user@example.com",
  "reason": "manual",
  "notes": "Requested removal from mailing list",
  "created_at": "2025-06-15T10:30:00.000Z"
}

DELETE/v1/suppressions/:idAPI Key

Remove a suppression entry, allowing the email address to receive emails again.

Parameter	Type	In	Description
`id`required	`string`	path	Suppression entry UUID

Response

json

{
  "success": true
}

SMTP Relay

Sandbox Mode