Skip to main content

Client Integration

Use r402-http client middleware to automatically handle x402 payments when making HTTP requests from Rust.

Installation​

cargo add r402 r402-evm r402-http --features client

Basic Example​

use alloy_signer_local::PrivateKeySigner;
use r402_evm::Eip155ExactClient;
use r402_http::client::{ReqwestWithPayments, ReqwestWithPaymentsBuild, X402Client};
use std::sync::Arc;

let signer = Arc::new("0x…".parse::<PrivateKeySigner>()?);
let x402 = X402Client::new().register(Eip155ExactClient::new(signer));

let client = reqwest::Client::new()
    .with_payments(x402)
    .build();

let res = client.get("https://api.example.com/paid").send().await?;
println!("{}", res.text().await?);

How It Works​

  1. The client sends a normal HTTP request.
  2. If the server responds with 402 Payment Required:
    • The client middleware parses the price tag from the response.
    • It finds a registered scheme that can handle the payment.
    • The scheme signs a payment payload using your private key.
    • The request is retried with the X-PAYMENT header.
  3. If the payment is accepted, you receive the response normally.

Multi-chain Client​

Register multiple scheme clients to support payments on different chains:

use r402_evm::Eip155ExactClient;
use r402_svm::SolanaExactClient;

let x402 = X402Client::new()
    .register(Eip155ExactClient::new(evm_signer))
    .register(SolanaExactClient::new(solana_signer));

Client Hooks​

Use ClientHooks to observe or modify the payment flow:

use r402::hooks::ClientHooks;

// Hooks allow you to:
// - Log payment attempts and results
// - Implement retry logic
// - Add custom headers
// - Track spending
  • Server — gate endpoints with payments
  • Chains — list of supported chains and tokens