Manage the Resend suppression list: what lands there and what never leaves

TL;DR: A workflow for the suppression list: which events add addresses automatically, how to add them manually via API, and the rule that a suppressed address is never mailed again without explicit re-consent. Check before every send. Subscribe to the suppressions.added webhook event so your app learns about suppressions in real time, including the automatic ones, and stops scheduling sends to those addresses from your side too. Add addresses manually through the suppressions API when a user asks to stop all mail or you detect abuse.

The fix

1. Know what lands there automatically: hard bounces and spam complaints add the address without your code doing anything. Soft bounces do not suppress; they retry. Docs: https://resend.com/docs/dashboard/emails/email-suppressions
2. Subscribe to the suppressions.added webhook event so your app learns about suppressions in real time, including the automatic ones, and stops scheduling sends to those addresses from your side too.
3. Add addresses manually through the suppressions API when a user asks to stop all mail or you detect abuse. Manual adds and batch adds are both supported; use batch for list cleanups.
4. Never remove an address from suppression to resume mailing unless the owner explicitly re-opted in through your product. Removing a complained address and mailing it again is the fastest way to a second complaint and a damaged reputation.
5. Before any large send, cross-check your recipient list against the suppression list via the API. Your code should treat a suppressed address as a hard stop, not a warning.
6. Distinguish suppression from unsubscribe: suppression is Resend refusing to deliver, unsubscribe is the contact opting out of marketing. Handle both, and make sure a suppressed contact is also unsubscribed so broadcasts skip them cleanly.
7. Audit monthly: review suppressions.removed events and confirm every removal traces back to a real re-consent action, not a bulk cleanup script.

When to use this

• This covers exactly what the title says: Manage the Resend suppression list.
• You are setting this up for the first time, or auditing an existing setup.
• You want the key gotchas in one place before you start.

When not to use this

• You are doing a different workflow with Manage; these steps are specific to the title above.
• You need the full reference docs; this is the short path, not the manual.

Compatibility

• Not pinned to a specific version; follows current Manage behavior.

Edge cases

• Never remove an address from suppression to resume mailing unless the owner explicitly re-opted in through your product.

Verified against the Resend suppression docs and webhook event-types on 2026-09-26: hard bounces and spam complaints add addresses automatically, suppressions.added and suppressions.removed events track changes, and suppressed addresses must never be mailed again without explicit re-consent.