CryptoPay - Etherscan Payment Gateway

A Rust library for verifying and monitoring cryptocurrency payments on Ethereum using the Etherscan API.

Features

• ✅ Etherscan API Integration - Complete API coverage for accounts, transactions, tokens, and gas
• 💰 Payment Verification - Verify ETH and ERC20 token payments with confirmation tracking
• 👀 Payment Monitoring - Real-time monitoring with customizable callbacks
• ⚡ Rate Limiting - Built-in token bucket rate limiter (5 req/s default)
• 💾 Caching - In-memory LRU cache with configurable TTL
• 🔄 API Key Rotation - Round-robin rotation for multiple API keys
• 🎯 Type Safety - Strongly-typed models with helper methods

Quick Start

[dependencies]
cryptopay = "0.1"
tokio = { version = "1", features = ["full"] }
rust_decimal = "1.33"

use cryptopay::*;
use rust_decimal::Decimal;

#[tokio::main]
async fn main() -> Result<()> {
    let client = EtherscanClient::new("your-api-key")?;
    let verifier = PaymentVerifier::new(client);
    
    let payment = PaymentRequest::eth(
        Decimal::new(1, 1), // 0.1 ETH
        "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0",
        12, // confirmations
    );
    
    match verifier.verify_payment(&payment).await? {
        VerificationResult::Confirmed { tx_hash, .. } => {
            println!("✅ Payment confirmed: {}", tx_hash);
        }
        _ => println!("⏳ Payment pending or not found"),
    }
    
    Ok(())
}

Documentation

• 📚 API Documentation
• 📖 User Guide
• 🚀 Examples
• 📝 CHANGELOG

Examples

See the examples/ directory for complete examples:

• basic_payment.rs - ETH payment verification
• token_payment.rs - ERC20 token verification
• payment_monitor.rs - Real-time monitoring with callbacks

Run examples:

ETHERSCAN_API_KEY=your-key cargo run --example basic_payment

Configuration

Environment Variables

export ETHERSCAN_API_KEY="your-api-key"
export ETHERSCAN_RATE_LIMIT=5
export ETHERSCAN_CACHE_TTL=300

Builder Pattern

let config = ClientConfig::builder()
    .api_key("key1")
    .api_key("key2")  // Multiple keys for rotation
    .rate_limit(10)   // Higher limit for PRO plan
    .testnet()        // Use Sepolia testnet
    .build()?;

let client = EtherscanClient::with_config(config)?;

Supported Currencies

// Native ETH
Currency::ETH

// Predefined tokens
Currency::usdt()  // Tether (6 decimals)
Currency::usdc()  // USD Coin (6 decimals)
Currency::dai()   // Dai (18 decimals)

// Custom ERC20
Currency::erc20("0xcontract...", 18)

Getting an API Key

1. Visit Etherscan
2. Create an account
3. Go to API-KEYs section
4. Generate a free API key

License

Licensed under either of:

• MIT license LICENSE

at your option.

Contributing

Contributions welcome! Please feel free to submit a Pull Request.