x402 Rust Implementation

A high-performance, type-safe Rust implementation of the x402 HTTP-native micropayment protocol.

📦 Installation

Add this to your Cargo.toml:

[dependencies]
rust-x402 = "0.2.2"

✨ Features

🚀 HTTP-native micropayments: Leverage the HTTP 402 status code for payment requirements
⛓️ Blockchain integration: Support for EIP-3009 token transfers with real wallet integration
🌐 Web framework support: Middleware for Axum, Actix Web, and Warp
💰 Facilitator integration: Built-in support for payment verification and settlement
📦 Standalone facilitator: Production-ready facilitator server as standalone binary
🗄️ Redis storage: Optional Redis backend for distributed nonce storage
🔒 Type safety: Strongly typed Rust implementation with comprehensive error handling
🧪 Comprehensive testing: 114 tests with 100% pass rate covering all real implementations
🏗️ Real implementations: Production-ready wallet, blockchain, and facilitator clients
🌊 Multipart & Streaming: Full support for large file uploads and streaming responses
📡 HTTP/3 Support: Optional HTTP/3 (QUIC) support for modern high-performance networking

🚀 Quick Start

Creating a Payment Server with Axum

use axum::{response::Json, routing::get};
use rust_x402::{
    axum::{create_payment_app, examples, AxumPaymentConfig},
    types::FacilitatorConfig,
};
use rust_decimal::Decimal;
use std::str::FromStr;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create facilitator config
    let facilitator_config = FacilitatorConfig::default();
    
    // Create payment configuration
    let payment_config = AxumPaymentConfig::new(
        Decimal::from_str("0.0001")?,
        "0x209693Bc6afc0C5328bA36FaF03C514EF312287C",
    )
    .with_description("Premium API access")
    .with_facilitator_config(facilitator_config)
    .with_testnet(true);

    // Create the application with payment middleware
    let app = create_payment_app(payment_config, |router| {
        router.route("/joke", get(examples::joke_handler))
    });

    // Start server
    let listener = tokio::net::TcpListener::bind("0.0.0.0:4021").await?;
    axum::serve(listener, app).await?;

    Ok(())
}

💳 Making Payments with a Client

use rust_x402::client::X402Client;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = X402Client::new()?;
    
    // Make a request to a protected resource
    let response = client.get("http://localhost:4021/joke").send().await?;
    
    if response.status() == 402 {
        println!("Payment required! Status: {}", response.status());
        // Handle payment required - parse PaymentRequirements and create signed payload
        // See examples/client.rs for complete implementation
    } else {
        let text = response.text().await?;
        println!("Response: {}", text);
    }
    
    Ok(())
}

🏭 Running the Standalone Facilitator Server

The facilitator can run as a standalone binary with optional Redis storage:

# In-memory storage (default)
cargo run --bin facilitator --features axum

# Redis storage backend
STORAGE_BACKEND=redis cargo run --bin facilitator --features axum,redis

# Custom configuration
BIND_ADDRESS=0.0.0.0:4020 \
REDIS_URL=redis://localhost:6379 \
REDIS_KEY_PREFIX=x402:nonce: \
cargo run --bin facilitator --features axum,redis

🏗️ Architecture

The Rust implementation is organized into several modules:

📦 types: Core data structures and type definitions
🌐 client: HTTP client with x402 payment support
💰 facilitator: Payment verification and settlement
🗄️ facilitator_storage: Nonce storage backends (in-memory and Redis)
🔧 middleware: Web framework middleware implementations
🔐 crypto: Cryptographic utilities for payment signing
❌ error: Comprehensive error handling
🏦 wallet: Real wallet integration with EIP-712 signing
⛓️ blockchain: Blockchain client for network interactions
🏭 blockchain_facilitator: Blockchain-based facilitator implementation
📡 http3: HTTP/3 (QUIC) support (feature-gated)
🔄 proxy: Reverse proxy with streaming support

🌐 Supported Web Frameworks

🚀 Axum: Modern, ergonomic web framework
⚡ Actix Web: High-performance actor-based framework
🪶 Warp: Lightweight, composable web server

🌐 HTTP Protocol Support

✅ HTTP/1.1: Full support with chunked transfer encoding
✅ HTTP/2: Full support with multiplexing
✅ Multipart: Support for multipart/form-data uploads (via multipart feature)
✅ Streaming: Chunked and streaming responses (via streaming feature)
🔜 HTTP/3 (optional): QUIC-based HTTP/3 via http3 feature flag

🎛️ Optional Features

x402 supports optional features for a modular build:

[dependencies]
rust-x402 = { version = "0.2.2", features = ["http3", "streaming", "multipart"] }

http3: Enable HTTP/3 (QUIC) support
streaming: Enable chunked and streaming responses
multipart: Enable multipart/form-data upload support (requires streaming)
redis: Enable Redis backend for facilitator storage
axum: Enable Axum web framework integration (default)
actix-web: Enable Actix Web framework integration
warp: Enable Warp web framework integration

⛓️ Blockchain Support

Currently supports:

🏛️ Base: Base mainnet and testnet
❄️ Avalanche: Avalanche mainnet and Fuji testnet
📜 EIP-3009: Transfer with Authorization standard

📚 Examples

See the examples/ directory for complete working examples:

🚀 axum_server.rs: Payment server using Axum
💳 client.rs: Client making payments
💰 facilitator.rs: Custom facilitator implementation
🏦 real_implementation_demo.rs: Real wallet and blockchain integration
🔐 real_wallet_integration.rs: Production-ready wallet integration

📊 Testing

✅ 114 tests with 100% pass rate
🧪 Comprehensive coverage of all real implementations
🔍 Integration tests for end-to-end workflows
🛡️ Error handling tests for robust error scenarios
🌊 Multipart & streaming tests for file upload/download scenarios
📡 HTTP/3 tests (with http3 feature)
🗄️ Redis storage tests with auto-skip when unavailable
⚙️ Feature-gated tests for modular builds

📄 License

Licensed under the Apache License, Version 2.0. See LICENSE for details.

rust-x402 0.2.2