Voice API - Programmable PSTN & VoIP Calls

What is the Voice API?

The EnableX Voice API is a REST-based platform for programmable voice. Unlike traditional PBX systems or simple request-response APIs, the Voice API is webhook-driven. Your application initiates a call, and then your server receives real-time webhooks for every call event — when someone answers, when they press a key, when they speak. You respond to each webhook with an action (play audio, collect input, transfer the call), and the platform executes it. This gives you complete control over the call flow.

What You Can Build

With the Voice API, you can build:

• Outbound calls — Dial from your application to any phone number. Answer detection, callback handling, caller ID control.
• IVR (Interactive Voice Response) — Play menus, collect DTMF input, route based on user input, build complex call trees.
• Inbound call routing — Receive calls on DID numbers, route to agents, voicemail, or external systems.
• Call recording — Record inbound or outbound calls for compliance, training, or quality assurance.
• Call Bridging — Connect two call legs together to form a two-party conversation. See Call Bridging in the Voice API Reference.
• Text-to-speech (TTS) — Play dynamically generated audio announcements, confirmations, or alerts.
• Speech-to-text (ASR) & DTMF collection — Collect voice input or keypad presses, feed into AI systems.

How It Works (The Control Loop)

The Voice API works through a simple loop:

1. Initiate — Your app server calls POST /voice/v1/call with a phone number and your webhook URL.
2. Event — The EnableX platform dials the number. When something happens (call answered, key pressed, timeout), it sends a webhook POST to your server.
3. Respond — Your server receives the webhook, processes it, and responds with a JSON action (talk, play, collect, transfer, hangup, etc.).
4. Execute — The platform executes the action and waits for the next event.
5. Repeat — Steps 2–4 repeat until the call ends.

This loop continues until you hang up the call or the caller disconnects. Your server stays in control the entire time.

Key API Operations

Authentication

All Voice API requests use HTTP Basic Authentication. Encode your App ID and App Key as Base64(APP_ID:APP_KEY) and pass it in the Authorization header. The example below initiates an outbound call that plays a TTS prompt when answered:

curl -X POST https://api.enablex.io/voice/v1/call \
  -H "Authorization: Basic $(echo -n 'APP_ID:APP_KEY' | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "my-service",
    "from": "Your_EnableX_Number",
    "to": "Destination_Number",
    "action_on_connect": {
      "play": {
        "text": "Hello! This is a test call from EnableX.",
        "language": "en-US",
        "voice": "female"
      }
    },
    "event_url": "https://yourdomain.com/webhook"
  }'

Your App ID and App Key are found in the EnableX Portal under Project Settings › API Credentials. Keep your App Key secure — never commit it to version control or expose it in client-side code.

Documentation Map

Start here based on what you're building:

Related Products

• Video API — Add video conferencing to your app. Browser-based video calls with WebRTC.
• Messaging API — SMS, WhatsApp, RCS messaging. Complementary to Voice for multi-channel engagement.
• Video Embed — Pre-built video UI components for quick integration.
• Analytics Dashboard — Monitor call volume, duration, costs, and quality metrics.