Forward Thread Email
Forward a message in an inbox thread to new recipients.
POST
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: trueheader - 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
Response Fields
string
The ID of the sent email. Use it with the emails
endpoints.