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Inboxes are currently in private beta and only available to a limited number of users. The response shape might change before GA.Get early access if you’re interested in testing this feature.Once you have access, upgrade your Resend SDK to use the new methods:
A draft lets you prepare a message before sending it. Omit thread_id and reply_to_email_id to start a new thread. Pass both for a reply draft. An email can have only one unsent reply draft. A request for an email that already has one returns a 200 with the existing Draft ID. It changes only the attachments of that draft.

Path Parameters

Body Parameters

At least one of to, cc, bcc, subject, text, html, or attachments must be non-empty. to, cc, and bcc combined cannot exceed 50 recipients.
string | string[] | null
Recipients. For multiple addresses, send an array of strings. Each value can include a friendly name, for example Ada Lovelace <ada@example.org>. On a reply draft, when you omit to or send null, the draft gets the recipients of a reply. Send [] for no recipients.
string | string[] | null
CC recipients.
string | string[] | null
BCC recipients.
string | null
The subject. 1 to 2000 characters, with no line breaks.
string | null
The HTML body.
string | null
The plain-text body.
array | null
Files to store on the draft, up to 25 MB in total. Drafts do not accept path or content_id.

Headers

string
Add an idempotency key to prevent duplicated drafts.
  • Should be unique per API request
  • Idempotency keys expire after 24 hours
  • Have a maximum length of 256 characters
  • A retry with the same key returns the first successful response, with the idempotent-replayed: true header
  • A failed request is not stored, so you can retry it with the same key
  • Reusing the key with a different body, or while the first request is still running, returns a 409
Learn more

Response Fields

string
Always inbox_draft.
string
The ID of the draft.