# `Letterbox.Ingress.Resend`
[🔗](https://github.com/hattoriai/letterbox/blob/v0.1.0-rc.0/lib/letterbox/ingress/resend.ex#L1)

[Resend](https://resend.com)'s inbound emails.

    config :letterbox, ingresses: [resend: [secret: "whsec_…", api_key: "re_…"]]

In Resend, a webhook for the `email.received` event, to its route
(`https://<app>/inbound/webhooks/resend`, as `mix letterbox.install`
writes it), and its signing secret as
`:secret`. `:api_key` is a key of the account, which reads its emails.

The webhook carries an email's id and envelope, not the email: Letterbox
answers it at once, then fetches the email (`GET /emails/receiving/:id`)
and its raw message (`raw.download_url`) out of the request, tried again
while Resend has not got it. The recipients are Resend's
`received_for`, the addresses it took the email for (`Bcc` included).

The request is signed by Svix (`svix-id`, `svix-timestamp`,
`svix-signature`): an HMAC-SHA256 of `"<id>.<timestamp>.<body>"` with the
secret (Base64, after `whsec_`), and one more than five minutes away is
refused.

Options: `:secret`, `:api_key`, `:base_url` (`https://api.resend.com`),
and `:req_options`, given to `Req` (for tests, `plug:`).

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*Consult [api-reference.md](api-reference.md) for complete listing*