Broadcasts

A broadcast is a one-to-many send (a newsletter, announcement, or digest) delivered to your contacts on a broadcast stream, so unsubscribed contacts are skipped automatically.

Create

curl https://api.sendsignal.dev/broadcasts \
  -H "Authorization: Bearer ss_..." -H "Content-Type: application/json" \
  -d '{
    "name": "August newsletter",
    "from": "Acme <news@acme.com>",
    "subject": "New in August",
    "html": "<p>…</p>"
  }'

Fields: name, from, subject, and content as html/text or a template_id. Target one audience slice with segment_id (a segment) or topic_id (subscribers of a topic); omit both to send to every subscribed contact. An optional scheduled_at sets a default send time.

Send, schedule, cancel

• POST /broadcasts/{id}/send: fire it. Pass {"immediate": true} to send now, or {"scheduled_at": "2026-09-01T09:00:00Z"} to schedule.
• POST /broadcasts/{id}/cancel: cancel a scheduled broadcast before it goes out.
• GET /broadcasts / GET /broadcasts/{id}: list and inspect (including send progress).
• DELETE /broadcasts/{id}: remove.

Each recipient becomes a normal email with its own delivery events, so webhooks and stats work exactly as for transactional sends.