What’s in This SDK?
SDK Purpose
The Click To Call SDK helps developers:- Establish real-time voice calls between a user’s browser and Cognigy Voice Gateway using SIP signaling and the WebRTC API.
- Manage the full call lifecycle through a simple, promise-based API: connect, start, mute, unmute, send info messages, and disconnect.
- Handle remote audio playback automatically. The SDK manages audio element creation and stream attachment internally, with an optional
captureAudioevent for advanced audio processing. - Receive real-time transcription events during calls, with automatic separation from regular info messages.
Requirements
| Requirement | Details |
|---|---|
| Language | JavaScript or TypeScript. The SDK is framework-agnostic and works with React, Angular, Vue, or vanilla JS. |
| Node.js | 16 or later |
| Package manager | npm |
| Browsers | Modern web and mobile browsers. For more information, refer to Supported Browsers. |
| Network | HTTPS or localhost. WebSocket and UDP traffic must be allowed. |
| Backend | A Cognigy.AI environment with a configured Voice Gateway Endpoint. |
Use Cases
- Build multimodal browser-based voice interfaces that connect to Cognigy AI Agents.
- Embed click-to-call functionality into web applications or customer portals.
- Display real-time transcription of voice conversations in your UI.
- Integrate voice calling into existing React, Angular, Vue, or vanilla JS applications without framework lock-in.
Key Features
| Feature | Description |
|---|---|
| Custom Audio Handling | The SDK handles remote audio playback automatically via an internal Audio element. For advanced use cases, set captureAudio: true in the client config to receive the raw MediaStream via the captureAudio event. The audioEnded event notifies when playback stops. See Custom Audio. |
| Full Call Control | Complete call control: start, end, mute, unmute, and send info messages — all as simple async methods. See API reference. |
| Multimodality | The SDK supports multimodal interactions by combining voice, text, and structured data in real time. The sendInfo method lets you send text and optional structured data during calls, making your interface fully multimodal. See API Reference: sendInfo. |
| Event-Driven Architecture | Rich pub/sub event system with 17 events covering connection state, call state, audio, transcription, and errors. See Event Reference. |
| Real-Time Transcription | Receive transcription events during calls. Transcription data is automatically filtered from regular info messages. See Event Reference: transcription. |
Changelog Reference
The latest SDK version is available on npm as@cognigy/click-to-call-sdk. For updates and fixes, refer to the Cognigy Click To Call SDK GitHub repository.
License
The Cognigy Click To Call SDK is licensed under the MIT License.Next Steps
- Getting Started — install the SDK, create a client, and make your first voice call
- API Reference — explore all methods, configuration options, and types
- Event Reference — discover all 17 events with callback signatures and examples
- Security — transport encryption, credential handling, and best practices
- Initialization and Authentication — how the SDK authenticates with the Cognigy backend
- Troubleshooting — find solutions for common connection, call, and browser issues