I Built a Free Cold Calling Dialer That Replaces $200/Month Software

Most cold calling tools cost $50-200 per user per month. I built one that's free, open-source, and runs in your browser.

The Problem

I was working with a small sales team that needed to make cold calls. They looked at:

• RingCentral — $30/user/month
• Dialpad — $25/user/month
• Five9 — $150+/user/month
• Vicidial — Free but requires a dedicated server and is ancient

None of these fit their budget or needs. So I built Open Cold Dialer.

What It Does

It's a full-featured cold calling CRM that runs in your browser:

Core Features

• Browser Softphone — Make calls directly from your browser using SIP.js
• Multi-Provider SIP — Works with SignalWire, Telnyx, Twilio, or any SIP server
• Lead Management — Add leads manually or import from CSV
• Campaign Management — Organize leads into campaigns
• Call Scripts — Templates with objection handling responses
• Call History — Track every call with outcome and notes
• Dashboard — Real-time stats on your calling activity

Tech Stack

Frontend:  React 18 + Vite + TypeScript + Tailwind CSS
Backend:   Express.js + SQLite (zero config!)
Auth:      JWT with bcrypt
SIP:       SIP.js (WebRTC)

How It Works

1. Self-Hosted (Recommended)

git clone https://github.com/6t9xstar/Open-Cold-Dialer.git
cd Open-Cold-Dialer

# Backend
cd backend
npm install
npm run seed  # Loads 20 sample leads
npm run dev

# Frontend (new terminal)
cd frontend
npm install
cp .env.example .env.local
npm run dev

Open http://localhost:3000 and you're running.

2. Docker

docker compose up -d
docker compose exec backend npm run seed

3. With Real SIP Calls

Add your SIP provider credentials to .env.local:

VITE_SIP_URI=sip:[email protected]
VITE_SIP_PASSWORD=your-password
VITE_SIP_WS_URL=wss://your-domain.sip.signalwire.com
VITE_SIP_CALLER_ID=+1XXXXXXXXXX

The Architecture

┌─────────────────────────────────────────────┐
│                  Browser                     │
│  ┌─────────┐  ┌──────────┐  ┌───────────┐  │
│  │ React UI│  │ SIP.js   │  │ WebRTC    │  │
│  │         │  │ Client   │  │ Audio     │  │
│  └────┬────┘  └────┬─────┘  └─────┬─────┘  │
│       │            │              │         │
└───────┼────────────┼──────────────┼─────────┘
        │            │              │
   ┌────▼────┐  ┌────▼─────┐  ┌────▼─────┐
   │ Express │  │ SignalWire│  │ Browser  │
   │ API     │  │ / Telnyx  │  │ Mic      │
   │ (REST)  │  │ (SIP)     │  │          │
   └────┬────┘  └──────────┘  └──────────┘
        │
   ┌────▼────┐
   │ SQLite  │
   │ DB      │
   └─────────┘

The key insight: SIP.js handles the telephony directly from the browser. No need for a SIP server — just connect to your provider's WebSocket endpoint.

Why I Chose These Tools

SIP.js

The library that makes browser-based calling possible. It handles:

• SIP registration
• Making/receiving calls
• Audio via WebRTC
• DTMF tones

SQLite

Zero-config database. No PostgreSQL, no MySQL — just a file. Perfect for:

• Single-server deployments
• Easy backup (copy one file)
• No database admin needed

Vite

Blazing fast development. Hot module replacement means changes appear instantly.

Comparison with Alternatives

*Vicidial is free but requires a dedicated server and is complex to set up.

What's Next

I'm working on these features:

• [ ] Audio device selector (choose mic/speaker)
• [ ] Call recording
• [ ] Parallel dialing (power dialer mode)
• [ ] Voicemail detection
• [ ] DNC list management
• [ ] AI call summaries

Try It Out

The project is open-source and ready to use:

GitHub: github.com/6t9xstar/Open-Cold-Dialer

git clone https://github.com/6t9xstar/Open-Cold-Dialer.git
cd Open-Cold-Dialer/backend && npm install && npm run seed && npm run dev

If you find it useful, please give it a star on GitHub. It helps others discover the project.

Questions?

Open an issue on GitHub or drop a comment below. I'm happy to help you set it up.

Built with React, TypeScript, SIP.js, and a lot of coffee.