Series: Building Cloud Call Centres with Vonage APIs — Day 4 of 30

Vonage Client SDK: Building Your First Voice App for a Cloud Call Centre ← Day 3: Setup from Scratch | Day 5: Call Routing & Business Rules → 🎯 What You'll Build Today By the end of this post you will have: ✅ A browser-based softphone that receives inbound calls ✅ An agent login system using Vonage JWTs ✅ Answer / Hang up / Mute controls working in the browser ✅ Real-time call status display (ringing, connected, duration) ✅ Your first working agent desktop component No phone hardware. No SIP client. Just a browser tab. 🗺️ What We're Building ┌──────────────────────────────────────────────────────────────────┐ │ TODAY'S ARCHITECTURE │ │ │ │ Caller's Phone │ │ │ │ │ │ dials virtual number │ │ ▼ │ │ ┌──────────┐ webhook ┌──────────────┐ │ │ │ Vonage │──────────────► │ Your Node │ │ │ │ Platform │ │ Backend │ │ │ └────┬─────┘ ◄──── NCCO ───│ server.js │ │ │ │ └──────────────┘ │ │ │ WebRTC audio stream │ │ │ │ │ ▼ │ │ ┌──────────────────────────────────────────┐ │ │ │ AGENT'S BROWSER │ │ │