Developer Overview

How applications use Blendlix Call Service as a platform.

Developer Overview

Blendlix Call Service provides a reusable realtime calling layer for web and mobile applications.

Applications request a short-lived call token from their backend, connect to the realtime WebSocket endpoint, and use WebRTC for audio.

What you need as an integrator

PartOwner
User login and permissionsApplication backend
Deciding whether a call is allowedApplication backend
Requesting a call session tokenApplication backend
Showing call UIClient application
WebRTC microphone/audio handlingClient application
WebSocket signaling and call state authorityBlendlix Call Service
TURN/STUN ICE server detailsBlendlix Call Service

Integration model

  1. the backend checks that caller and receiver are allowed to talk
  2. the backend authenticates to Blendlix Call Service using product credentials
  3. the backend requests a short-lived call session token
  4. the backend returns the token, WebSocket URL, and ICE servers to the client
  5. the client connects to wss://.../v1/ws
  6. the client sends call events such as call.invite, call.accept, and call.end
  7. peers exchange WebRTC offer, answer, and ICE candidates over the WebSocket
  8. the audio media flows directly peer-to-peer where possible, with TURN used when needed

Product credentials are mandatory

The backend must send valid product credentials before Blendlix Call Service will issue a client session token.

Without these headers, the request is rejected:

  • X-BCS-Product-Key-ID
  • X-BCS-Product-Secret

Mobile or web clients must not call the session bootstrap endpoint directly. The bootstrap request should come from a trusted backend only.

Beginner-friendly mental model

Think of the call service as a secure phone switchboard:

  • the application backend is the receptionist that confirms the caller is allowed to call
  • Blendlix Call Service gives the caller a temporary call pass
  • the app uses that pass to enter the realtime WebSocket room
  • the two clients exchange WebRTC setup messages
  • after WebRTC connects, the voice audio travels between the two devices

Minimum integration checklist

To complete a working integration, prepare:

  1. Product credentials from Blendlix: key_id and secret
  2. A backend endpoint, for example /api/calls/session
  3. Permission checks inside the backend before requesting a token
  4. Client code that opens a WebSocket with the returned token
  5. Client call screens for outgoing, incoming, connected, ended, rejected, and missed states
  6. WebRTC audio-only peer connection using ice_servers from the token response
  7. A phone-call or normal-support fallback if the call service is unavailable