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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 is an unsent message. Omit thread_id and reply_to_email_id for a draft that starts a new thread. Pass both together for a reply draft in an existing thread. A reply draft without to is addressed to the sender of the email it replies to, or to its Reply-To when set. For an email the inbox sent, it defaults to that email’s to recipients. Send to: [] to leave it empty. cc, bcc, and subject are never filled in. At least one of to, cc, bcc, subject, text, html, or attachments must be non-empty. The combined recipients of to, cc, and bcc cannot exceed 50. Returns 201 for a new draft. Only one unsent reply draft can target an email, so a reply draft request for an email that already has one returns 200 with the ID of the existing draft. That request ignores every other field, except attachments, which replaces the attachments of the existing draft. A reply draft created without subject stores an empty subject and gets no Re: prefix. Set a subject before you send it.

Path Parameters

Body Parameters

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>.
string | string[] | null
CC recipients. For multiple addresses, send an array of strings.
string | string[] | null
BCC recipients. For multiple addresses, send an array of strings.
string | null
The subject. Max 2000 characters. A string that is only whitespace, or that contains a line break, is rejected.
string | null
The HTML body.
string | null
The plain-text body.
array
Files to store on the draft. Each one needs content, filename, and content_type. path and content_id return 422. An empty file or a blocked file type, such as .exe, returns 422. The files on a draft can total at most 25 MB. A file counts as draft content.

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.