REST endpoints, predictable JSON, key-based authentication.
The Send4Sale API lets you send SMS and WhatsApp messages, manage contacts and groups, and subscribe to delivery and incoming-message webhooks. Every key has scoped permissions configured in the dashboard.
Pass your API key in the Authorization header as a bearer token. Keys are issued from the dashboard and can be revoked at any time. The example below uses a fake demo key.
Authorization: Bearer demo_api_key_123 Content-Type: application/json
A minimal request to send an SMS through one of your Android devices.
curl -X POST //send4sale.com/api/send/sms \ -H "Authorization: Bearer demo_api_key_123" \ -H "Content-Type: application/json" \ -d '{ "recipient": "+15551234567", "message": "Hi {name}, your order #1042 has shipped." }'
Subscribe to events for sent, delivered, received and failed messages. Send4Sale POSTs JSON to your endpoint with an HMAC signature header for verification.
{
"event": "message.delivered",
"id": "msg_demo_42",
"to": "+15551234567",
"status": "delivered",
"timestamp": "2026-05-25T12:42:11Z"
}
Every send has a tracked status (sent / delivered / failed) with timestamps and retry information visible in the dashboard.