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Send a broadcast

POST
/v1/broadcasts/{id}/send

Starts sending a draft, now or at scheduled_at. Sending a broadcast that already started returns it as it is.

Authorization

bearerAuth
headerAuthorizationBearer <token>

A secret API key from the dashboard: coss_live_… for production environments, coss_test_… for sandbox environments.

Path Parameters

id*string

The broadcast's id.

Header Parameters

Coss-Version?"2026-10-10"

The API version (a date) to use for this request. Defaults to your organization's version, pinned to the latest one when it first used the API and upgraded from the dashboard. The SDK always sends the version it was built for.

Value in"2026-10-10"

Request Body

application/json
  1. body
scheduled_at?string

Omit to start right away.

Formatdate-time

Response Body

The broadcast.

application/json
  1. response
object*"broadcast"
Value in"broadcast"
id*string
name*string
status*string

draft (editable), scheduled, sending, paused (see pause_reason), sent, canceled, or failed (see error).

Value in"draft""scheduled""sending""paused""sent""canceled""failed"
audience_id*string|null
segment_id*string|null
topic*string|null
from*string
reply_to*array<string>
subject*string
preview_text*string|null
html*string|null
text*string|null
tracking*
rate_per_second*integer|null
scheduled_at*|
Formatdate-time
started_at*|
Formatdate-time
completed_at*|
Formatdate-time
canceled_at*|
Formatdate-time
recipients_estimated*|

How many contacts it would reach, counted when it started.

pause_reason*|

Why a paused broadcast waits: paused (by you), billing_hold, usage_limit, marketing_paused, account_suspended, sending_paused.

error*|null
stats*
created_at*string
Formatdate-time
updated_at*string
Formatdate-time
import { Coss } from "coss";const coss = new Coss({  apiKey: process.env.COSS_API_KEY,  baseUrl: "https://api.coss.com",});const { data, error } = await coss.email.broadcasts.send("bcast_01k7c8m4q2f3e9v6t5r1n0p8yz", {  scheduled_at: "2026-10-20T09:00:00Z",});
{  "object": "broadcast",  "id": "bcast_01k7c8m4q2f3e9v6t5r1n0p8yz",  "name": "October newsletter",  "status": "sent",  "audience_id": null,  "segment_id": "seg_01k7c8m4q2f3e9v6t5r1n0p8yz",  "topic": "newsletter",  "from": "Acme <news@acme.com>",  "reply_to": [],  "subject": "What's new, {{{contact.first_name|there}}}",  "preview_text": null,  "html": "<p>Hi {{{contact.first_name|there}}},</p>",  "text": null,  "tracking": {    "opens": true,    "clicks": true  },  "rate_per_second": null,  "scheduled_at": "2026-10-20T09:00:00.000Z",  "started_at": "2026-10-20T09:00:01.000Z",  "completed_at": "2026-10-20T09:12:40.000Z",  "canceled_at": null,  "recipients_estimated": 1200,  "pause_reason": null,  "error": null,  "stats": {    "recipients": 1200,    "sent": 1200,    "delivered": 1180,    "bounced": 6,    "complained": 1,    "failed": 0,    "opened": 540,    "clicked": 120,    "unsubscribed": 4  },  "created_at": "2026-10-15T12:00:00.000Z",  "updated_at": "2026-10-20T09:12:40.000Z"}