---
title: "POST /v1/mailboxes/{mailboxId}/broadcasts"
method: POST
path: "/v1/mailboxes/{mailboxId}/broadcasts"
---

# POST /v1/mailboxes/{mailboxId}/broadcasts

`POST /v1/mailboxes/{mailboxId}/broadcasts`

## Request

- The document declares no server URL.
- Auth: one of:
  - OAuth 2 (authorization code, authorization URL `/authorize`, token URL `/oauth/token`, scopes: `email.write`)
  - HTTP bearer

Draft a broadcast. Sends nothing until it is dispatched.

## Path parameters

- `mailboxId` string, required

## Request body

- BroadcastCreate
  - `audienceId` string, required
  - `templateId` string, required
  - `from` string, required: **Required — a broadcast has no default sender, any more than a send does.** It must route into THIS mailbox — the one the broadcast belongs to and accounts for every recipient of — resolved as inbound mail is: the exact address, then without its `+tag`, then the domain's catch-all. Checked here, and again at dispatch, since routes can change between the two.

## Response `201`

The request has succeeded and a new resource has been created as a result.

- Broadcast
  - `id` string, required
  - `audienceId` string, required
  - `templateId` string, required
  - `from` string, required: The address every recipient is sent from, as the rail will send it.
  - `status` 'draft' | 'sending' | 'sent', required
  - `recipientCount` integer, required: Audience members discovered so far, including those it will not send to (see `BroadcastProgress.skipped`). 0 until dispatch enumerates the audience on the queue.
  - `createdAt` string, date-time, required
  - `sentAt` string, date-time, nullable, required

## Other responses

- `401`: Access is unauthorized.
- `403`: Access is forbidden.
- `404`: The server cannot find the requested resource.
- `422`: Client error
- `default`: An unexpected error response.

---

[API](https://skmtc.dev/foundermail/apis/mailbox.md) - [All operations](https://skmtc.dev/foundermail/apis/mailbox/llms.txt) - [OpenAPI document](https://skmtc.dev/foundermail/apis/mailbox/revisions/6a50628a86ed?raw)