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POST
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:
Forwards a message from the inbox address right away, with no stored draft. to is required. The original message is quoted under a forwarded-message banner, below the optional html or text note. The attachments of the original message are sent with the forward, together with any attachments you add. The request fails when they exceed 10 files or 25 MB of content in total. An original attachment that was sent from a URL (path) cannot be forwarded, and the request returns a 422. The forward carries the same In-Reply-To and References headers as a reply to the original message, so mail clients may group it with the original conversation. These headers can’t be set or overridden.

Path Parameters

Body Parameters

string | string[]
required
Recipient email address. For multiple addresses, send as an array of strings. Must name at least one address. to, cc, and bcc combined cannot exceed 50 recipients.
string | string[]
CC recipient email address. For multiple addresses, send as an array of strings. Counts toward the 50-recipient limit with to.
string | string[]
BCC recipient email address. For multiple addresses, send as an array of strings. Counts toward the 50-recipient limit with to.
string
An HTML note sent above the quoted original.
string
A plain-text note sent above the quoted original.
string
The subject of the forward. Max 2000 characters. Cannot contain a line break. When omitted, the thread subject is used, prefixed with Fwd: if it does not already start with it.
array
Files to attach, as on Send Email. Each one needs content or path. They share one limit with the attachments of the original message, which the forward also sends. Together they can have up to 10 files and at most 25 MB of content. A path file counts toward the 10 files only, because it is fetched when the email is sent. An empty file, a blocked file type, or a path that is not an http or https URL, or that points to localhost, returns a 422.
object
Custom headers to add to the email. Resend sets the In-Reply-To, References, and Reply-To headers, so you cannot set them here. Sending one of them, in any letter case, returns a 422. A header name cannot be empty, and names and values cannot contain line breaks or null characters, or the request returns a 422.

Headers

string
Add an idempotency key to prevent duplicated emails.
  • 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
The ID of the sent email. Use it with the emails endpoints.