Sending messages

POST /v1/messages/send is the single endpoint for every channel.

Required fields

to, channel (one of sms, rcs, whatsapp, email, voice) and message are required — or pass a channels array instead of channel/fallback (see below).

Channel fallback

Provide an ordered fallback list, or the newer channels array with the primary channel first:

{
  "to": "+4512345678",
  "channels": ["whatsapp", "sms"],
  "message": "Your order has shipped."
}

If WhatsApp delivery fails, the platform automatically retries on SMS — no separate API call.

Channel-specific fields

• Email: set subject, and htmlmessage (or the legacy html alias) for the HTML body. message is the plain-text fallback.
• WhatsApp: pass a whatsapp object, e.g. { "template": "order_shipped" }, for template messages outside the 24-hour session window.
• Voice: pass a voice object (e.g. { "voice": "female", "language": "da-DK" }) for TTS parameters.
• Sender ID: sender must be a sender ID approved in Settings → Sender IDs for SMS/RCS — unless your account has allow_unverified_sender enabled for system integrations.

Scheduling and per-message webhooks

scheduled_at (ISO timestamp) delays dispatch. webhook_url receives delivery status updates for this specific message — see Webhooks.

Marketing frequency caps

Pass a category (e.g. "newsletter") to have this send count against that category's frequency cap, configured account-wide in messaging policy — independent of the global cross-channel cap and any per-channel cap.

Response

{
  "message_id": "3fa1e2c0-...",
  "status": "queued",
  "channel": "sms",
  "to": "+4512345678",
  "cost": 0.045,
  "currency": "EUR",
  "created_at": "2026-07-08T10:00:00.000Z"
}

A 402 means insufficient balance or a missing payment method; 403 means the account is suspended, pending activation, or the sender ID isn't approved; 409 means the recipient has opted out of that channel.