OpenPix 🚀

A high-performance, clean-code .NET library for handling Brazilian PIX (EMV BR Code) payments.

🇧🇷 Leia em Português

💡 Why OpenPix?

Most PIX implementations in .NET rely on string concatenation and lack proper validation. OpenPix was built with Domain-Driven Design (DDD) and Performance in mind.

• ⚡ High Performance: Uses ReadOnlySpan<char> for parsing, avoiding unnecessary string allocations.
• 🛡️ Bulletproof Validation: Validates CRC-16 checksums, EMV field lengths, and CPF/CNPJ check digits (Mod11) ensuring no invalid keys are generated.
• ✨ Clean Code: Exposes a fluent API and rich Domain Objects (Merchant, TransactionId) instead of raw strings.
• 🔗 Dynamic & Static: Supports both Static PIX (Pix Key) and Dynamic PIX (PSP/Bank URL).
• 📦 Modular: The Core library (OpenPix.Core) has zero dependencies.

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🚀 Installation

1. The Core (Parser & Generator)

Lightweight, pure logic, zero dependencies.

dotnet add package OpenPix.Core

2. ASP.NET Core Integration (Dependency Injection)

Global configuration and injection for Web APIs.

dotnet add package OpenPix.AspNetCore

3. Visual Extension (Optional)

If you need to render the QR Code image (PNG/SVG).

dotnet add package OpenPix.QRCode

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⚡ Benchmarks

OpenPix is optimized for high-throughput scenarios.

1. Parsing (Reader)

Comparing PixParser against a traditional string manipulation:

Method	Mean	Allocated	Ratio
OpenPix	2.664 μs	272 B	1.00x
Naive Implementation	10.263 μs	15,824 B	3.85x

2. Building (Generator)

Comparing PixBuilder (Fluent API + Full Validation) against manual string concatenation:

Method	Mean	Allocated	Benefits
OpenPix	1.48 μs	1.83 KB	Less Memory, Full Validation, Clean Code
Naive Implementation	1.50 μs	3.02 KB	Error-prone, Hard to Maintain

> Result: OpenPix allows you to write cleaner and safer code while using 40% less memory than manual concatenation.

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📖 Usage

1. Generating a Static PIX (Pix Key)

Ideal for small businesses or P2P transfers.

using OpenPix; var payload = PixBuilder.Create() .WithKey("user@example.com") .WithMerchant("My Store Name", "Sao Paulo", "12345-000") // ZipCode (Optional) .WithAmount(12.50m) .WithTransactionId("ORDER12345") .Build();

Note: OpenPix automatically verifies CPF/CNPJ checksums (Mod11). If you pass an invalid key (e.g., typo), it will throw an exception immediately to prevent generating a useless QR Code.

2. Generating a Dynamic PIX (PSP URL)

Ideal for e-commerce integrations where the Bank/PSP provides a unique URL (Location).

var payload = PixBuilder.Create() .WithDynamicUrl("https://pix.example.com/qr/v2/9d36b84f-70b3-40a1") .WithMerchant("My Store Name", "Sao Paulo") .WithAmount(50.00m) // Optional for Dynamic, but recommended for display .Build();

3. Parsing and Validating (Reader)

Read a raw string, validate its CRC-16 signature, and hydrate a rich Domain Object.

using OpenPix; var rawString = "00020126..."; // Input from a user or scanner try { var pixData = PixParser.Parse(rawString); if (!string.IsNullOrEmpty(pixData.Url)) { Console.WriteLine($"Dynamic URL: {pixData.Url}"); } else { Console.WriteLine($"Pix Key: {pixData.PixKey}"); } Console.WriteLine($"Merchant: {pixData.Merchant?.Name}"); Console.WriteLine($"Amount: {pixData.Amount:C}"); Console.WriteLine($"TxID: {pixData.TxId.Value}"); } catch (ArgumentException ex) { Console.WriteLine("Invalid PIX Code or Checksum mismatch."); }

4. Rendering the QR Code

If you installed OpenPix.QRCode, you can convert the string directly to an image.

using OpenPix; using OpenPix.QRCode; // Import extension methods var payload = PixBuilder.Create()...Build(); // Generates a Base64 string ready for <img src="..."> // Automatically sets white background/black modules for banking app compatibility. string base64Png = payload.ToPngBase64(pixelsPerModule: 10); // Generates an SVG string for scalable vector graphics string svgContent = payload.ToSvg(); // Generates an ASCII Art string for console applications Console.WriteLine(payload.ToAsciiArt());

5. ASP.NET Core Integration

Easily expose an endpoint that generates Pix QR Codes on the fly using our minimal API extension.

Program.cs:

using OpenPix.AspNetCore; // Import namespace var builder = WebApplication.CreateBuilder(args); // 1. Add OpenPix services // Configure PixKey in appsettings.json or via options builder.Services.AddOpenPix(options => { options.PixKey = "user@example.com"; options.MerchantName = "My Store"; options.City = "Sao Paulo"; }); var app = builder.Build(); // 2. Map the generator endpoint (returns PNG image) app.MapPixQrCode("/api/pix/qrcode"); // Url example: /api/pix/qrcode?amount=10.50&txid=ORDER123 app.Run();

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🖥️ CLI Tool

You can use OpenPix directly from your terminal to generate and decode PIX strings.

Installation

# Run from source (dev) dotnet run --project src/OpenPix.Cli -- --help # Or install as a global tool (once packed) dotnet tool install -g OpenPix.Cli

Usage

Generate a Pix:

openpix gen --name "My Store" --city "Sao Paulo" --zip "12345-000" --key "user@example.com" --amount 10.50

Decode a Pix:

openpix decode "00020126..."

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🏗️ Architecture

This project follows Clean Architecture principles:

• OpenPix.Core:
  • Domain: Contains Value Objects (Merchant, TransactionId) that enforce business rules upon instantiation.
  • Infra: Contains low-level algorithms like Crc16 and EmvCodec.
  • No external dependencies.
• OpenPix.QRCode:
  • Depends on QRCoder to handle the graphical matrix generation.
  • Extends the Core functionality.

• OpenPix.AspNetCore: IServiceCollection extensions and IPixClient for Web APIs.

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🤝 Contribution

Contributions are welcome! Please check the Issues tab.

1. Fork the project.
2. Create your Feature Branch (git checkout -b feature/AmazingFeature).
3. Commit your changes (git commit -m 'Add some AmazingFeature').
4. Push to the Branch (git push origin feature/AmazingFeature).
5. Open a Pull Request.

📄 License

Distributed under the MIT License. See LICENSE for more information.