Retention.

Messages and events

Messages, their recipients, text and HTML bodies, and events are retained for 30 days from submission. The watcher sweeps expired records periodically, rather than promising deletion at the exact second of expiry.

After deletion, a details lookup returns ErrorCode 701. Export the information your application legitimately needs before the retention window ends; do not rely on the API as a permanent archive.

Attachments

Attachment contents are cleared once a message is sent. Filenames remain with its message during the retention window. The details endpoint returns filenames, never attachment downloads.

A queued or failed message can still retain attachment content until it is sent or its message is removed by the retention sweep.

Suppressions

Suppressions persist until explicitly reactivated. They are not removed when the original message expires. Keeping an address suppressed prevents repeated sends to a known bad recipient.

Test sends

Test keys do not create stored messages, recipients, bodies or events. The MessageID in a test response cannot be looked up, even immediately after the request.