Resend API (unofficial showcase)
POST/inboxes/{inbox_id}/drafts/{draft_id}/send

Send an inbox draft

Submits an unsent draft from the inbox address. A reply draft is sent in its existing thread, while a standalone draft starts a new thread; you can add custom headers in the optional request body. Before sending, the draft must have at least one recipient, a non-empty subject, and an HTML or plain-text body.

  • IdempotentThe SDK sends Idempotency-Key, so a retried request is only applied once.

3 parameters · 1 body field
inbox_idstringrequired
The UUID of the inbox containing the draft; an email address is not accepted.
draft_idstringrequired
The UUID of the draft to send.
Idempotency-Keystringoptional
A unique key to prevent duplicate sends; retries with the same key within 24 hours return the first successful response. If supplied, the key must be 1 to 256 characters.

Optional custom headers to add to the email when sending the draft.

headersobjectoptional
Custom headers to add to the email. The `In-Reply-To`, `References` and `Reply-To` headers are set by Resend and cannot be set here. Sending one of them, in any letter case, returns a 422. Header names cannot be empty, and names and values cannot contain line breaks or null characters, or the request returns a 422. `null` means no custom headers.

1 status code
200Returns the sent email's ID, which you can use with the emails endpoints.
idstringrequired
The ID of the sent email. Use it with the emails endpoints.

Error handling

The inbox_id and draft_id path parameters must be UUIDs identifying the inbox and draft. The Idempotency-Key header, if supplied, must contain 1 to 256 characters. The draft must have at least one to recipient, a non-empty subject, and an html or text body; custom headers cannot set In-Reply-To, References, or Reply-To, and header names and values cannot contain line breaks or null characters.