Send SMS & WhatsApp messages via API

Quick start

Send an SMS with just a few lines of code. The API uses standard JSON over HTTPS and returns a message ID you can use to track delivery status.

Send an SMS

// Send an SMS with just a few lines of code
const response = await echocue.sms.send({
  to: "+1234567890",
  message: "Your appointment is confirmed for tomorrow at 2pm"
});

// Response
{
  "success": true,
  "messageId": "msg_abc123"
}

Send a WhatsApp message

// Send WhatsApp with templates
const response = await echocue.whatsapp.send({
  to: "+1234567890",
  template: "order_shipped",
  variables: {
    name: "John",
    order_id: "#12345"
  }
});

// Response
{
  "success": true,
  "messageId": "msg_xyz789"
}

API capabilities

A complete API for SMS and WhatsApp messaging. Integrate in minutes, scale to millions of messages.

Common endpoints

Built for developers who want control

EchoCue gives you direct API access without per-message fees, with the flexibility to choose how messages are delivered.

Two messaging channels

SMS: Sent from your own phone number via our Android app. WhatsApp: Uses the WhatsApp Business API with approved templates - no app required.

Simple authentication

API Key + Secret authentication. Generate keys instantly from your dashboard. Rotate keys anytime. Include them in your request headers via the x-api-key and x-api-secret headers.

curl -X POST https://api.echocue.com/v1/sms/send \
  -H "x-api-key: your_api_key" \
  -H "x-api-secret: your_api_secret" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+1234567890",
    "message": "Hello from EchoCue"
  }'

No per-message fees

Flat monthly pricing with unlimited SMS on paid plans. No hidden costs or per-message charges.

Easy integration

RESTful JSON API with clear documentation. Works with any language or framework. Pre-built integrations for popular tools.

Connect with your favorite tools

Use our REST API directly, or connect through popular automation platforms.

What can you build?

Developers use EchoCue API for a variety of messaging automation use cases.

Developer questions