Connecting WebRTC and PSTN with OpenTok and Nexmo

At Nexmo, a new feature called SIP Connect has been announced which allows WebRTC endpoints to be connected to the Nexmo Voice API, enabling PSTN users to dial into an OpenTok video session. This enables the creation of real-time video web applications that can connect with both WebRTC and PSTN users. To build such an application, a Vonage API account is required, along with TokBox credentials for the real-time voice and video functionality. The application will need to be built using JavaScript or other compatible languages, and will require server-side code in Express.js to handle requests and connect with OpenTok. Key endpoints include /room/:roomId, /dial-out, /nexmo-answer, /nexmo-dtmf, and /hang-up, which are used for rendering the video session, dialing out via SIP, answering calls from the Nexmo Voice API, prompting for a PIN code, and hanging up the call respectively. The application also handles event webhooks to receive updates on call status changes.