Dawa 🦁

C# port of Baileys — a WhatsApp Web client library for .NET

Use WhatsApp from any .NET application (ASP.NET Core, IIS, console, worker service) without running a Node.js server.

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Why Dawa?

The Baileys library is great but requires Node.js. If you have an IIS / ASP.NET Core app, running a sidecar Node process adds complexity and points of failure. Dawa brings the WhatsApp Web protocol natively to .NET.

Name: Dawa is Swahili for "medicine" — it fixes the Node.js dependency problem.

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Features

• No Node.js — pure .NET 8 implementation
• QR code pairing — first-time auth via QR scan, just like Baileys
• Session persistence — saves credentials to disk, restores automatically
• Send text messages — to any phone number or JID
• Receive messages — event-driven, non-blocking
• ASP.NET Core DI — services.AddWhatsApp()
• Auto-reconnect — configurable reconnect on connection loss

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Architecture

┌─────────────────────────────────────────────┐
│               WhatsAppClient                 │  ← Public API
├─────────────────────────────────────────────┤
│           NoiseProcessor                    │  ← Noise XX handshake
│    Noise_XX_25519_AESGCM_SHA256             │
├─────────────────────────────────────────────┤
│     BinaryNode Encoder/Decoder              │  ← WA binary protocol
├─────────────────────────────────────────────┤
│          FrameSocket                        │  ← WebSocket + framing
│   wss://web.whatsapp.com/ws/chat            │
└─────────────────────────────────────────────┘

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Installation

dotnet add package Dawa.WhatsApp

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Quick Start

Console app

using Dawa;

await using var client = WhatsAppClient.Create("./wa-session");

// First run: fires QR code for scanning
client.QRCodeReceived += (_, qr) =>
{
    // Print to console, show in browser, generate image — your choice
    Console.WriteLine("Scan: " + qr);
    // Or use QRCoder to render in the terminal:
    // var qrCode = new AsciiQRCode(new QRCodeGenerator().CreateQrCode(qr, ECCLevel.L));
    // Console.WriteLine(qrCode.GetGraphic(1));
};

client.MessageReceived += (_, msg) =>
    Console.WriteLine($"{msg.From}: {msg.Text}");

await client.ConnectAsync();
await client.WaitUntilConnectedAsync();

await client.SendMessageAsync("+31612345678", "Hello from Dawa!");

ASP.NET Core / IIS

Program.cs:

builder.Services.AddWhatsApp(options =>
{
    options.SessionDirectory = "/var/whatsapp-session";
    options.AutoReconnect = true;
});

WhatsAppController.cs:

[ApiController]
[Route("api/whatsapp")]
public class WhatsAppController : ControllerBase
{
    private readonly WhatsAppClient _wa;

    public WhatsAppController(WhatsAppClient wa) => _wa = wa;

    [HttpPost("send")]
    public async Task<IActionResult> Send([FromBody] SendRequest req)
    {
        await _wa.SendMessageAsync(req.To, req.Text);
        return Ok();
    }

    [HttpGet("status")]
    public IActionResult Status() => Ok(_wa.State.ToString());
}

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QR Code

The QRCodeReceived event fires a raw QR string. Render it however you like:

// In console: use QRCoder ASCII
client.QRCodeReceived += (_, qr) => {
    var code = new AsciiQRCode(new QRCodeGenerator().CreateQrCode(qr, ECCLevel.L));
    Console.WriteLine(code.GetGraphic(1));
};

// In web: return QR as PNG
client.QRCodeReceived += async (_, qr) => {
    using var qrGen = new QRCodeGenerator();
    var data = qrGen.CreateQrCode(qr, ECCLevel.L);
    var png = new PngByteQRCode(data);
    await File.WriteAllBytesAsync("qr.png", png.GetGraphic(10));
};

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Protocol Implementation

Dawa implements the WhatsApp Web multi-device protocol:

Layer	Implementation
Transport	System.Net.WebSockets
Framing	3-byte big-endian length prefix
Encryption	Noise_XX_25519_AESGCM_SHA256
Key exchange	Curve25519 (BouncyCastle)
AEAD	AES-256-GCM (.NET built-in)
KDF	HKDF-SHA256 (.NET built-in)
Message format	Binary nodes (custom dict compression)
Serialization	Protobuf (Google.Protobuf)
E2E encryption	Signal Double Ratchet

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Limitations (v0.1)

• Text messages only (no media yet)
• No group management
• No presence / typing indicators
• Signal pre-key upload not yet automated (works after initial pairing)

These are all on the roadmap. PRs welcome!

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Compared to Baileys

Feature	Baileys (JS)	Dawa (C#)
Runtime	Node.js	.NET 8
IIS compatible	No	Yes
Text messages	Yes	Yes
Media	Yes	Planned
Groups	Yes	Planned
Session persistence	Yes	Yes
Auto-reconnect	Yes	Yes

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Contributing

1. Fork the repo
2. Create a feature branch: git checkout -b feat/my-feature
3. Commit your changes
4. Push and open a PR

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Legal

This library uses the WhatsApp Web protocol which is reverse-engineered. Use responsibly and in accordance with WhatsApp's Terms of Service. This project is not affiliated with or endorsed by Meta/WhatsApp.

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License

Apache 2.0 — see LICENSE.