x402-rs x402 SDK

x402-rs

A comprehensive Rust toolkit for the x402 protocol, enabling blockchain payments directly through HTTP using the native 402 Payment Required status code.

x402-rs is a modular, production-ready implementation of the x402 protocol with support for multiple blockchains (EVM, Solana, Aptos, ..) and protocol versions (V1 and V2).

Core Crates

Crate	Badges	Description
x402-types		Core protocol types, facilitator traits, and utilities. Foundation for all x402 implementations.
x402-axum		Axum middleware for protecting routes with x402 payments.
x402-reqwest		Reqwest middleware for transparent x402 payment handling.
x402-facilitator-local		Local facilitator implementation for payment verification and settlement.

Blockchain Support

Crate	Badges	Description
x402-chain-eip155		EVM/EIP-155 chain support (Ethereum, Base, Polygon, etc.)
x402-chain-solana		Solana blockchain support
x402-chain-aptos	⚠️ Git-only	Aptos blockchain support (requires git dependency)

Deployment

Crate	Description
x402-facilitator	Production-ready facilitator server binary (not published to crates.io)

About x402

The x402 protocol is a proposed standard for making blockchain payments directly through HTTP using the native 402 Payment Required status code.

How it works:

1. Server declares payment requirements for specific routes
2. Client sends cryptographically signed payment payloads
3. Facilitator verifies and settles payments on-chain

This enables seamless pay-per-use transactions without requiring clients to manage blockchain interactions directly.

Quick Start

Protect Routes (Server)

Use x402-axum to gate your routes behind on-chain payments:

use alloy_primitives::address;
use axum::{Router, routing::get};
use x402_axum::X402Middleware;
use x402_chain_eip155::V2Eip155Exact;
use x402_types::networks::USDC;

let x402 = X402Middleware::new("http://facilitator.example.com");

let app = Router::new().route(
    "/paid-content",
    get(handler).layer(
        x402.with_price_tag(V2Eip155Exact::price_tag(
            address!("0xYourAddress"),
            USDC::base_sepolia().amount(10u64),
        ))
    ),
);

See x402-axum documentation for more details.

Send Payments (Client)

Use x402-reqwest to automatically handle x402 payments:

use x402_reqwest::{ReqwestWithPayments, ReqwestWithPaymentsBuild, X402Client};
use x402_chain_eip155::V2Eip155ExactClient;
use alloy_signer_local::PrivateKeySigner;
use std::sync::Arc;
use reqwest::Client;

let signer: Arc<PrivateKeySigner> = Arc::new("0x...".parse()?);

let x402_client = X402Client::new()
    .register(V2Eip155ExactClient::new(signer));

let client = Client::new()
    .with_payments(x402_client)
    .build();

let res = client
    .get("https://example.com/protected")
    .send()
    .await?;

See x402-reqwest documentation for more details.

Run a Facilitator

Docker

Prebuilt Docker images are available at GitHub Container Registry:

docker run -v $(pwd)/config.json:/app/config.json -p 8080:8080 ghcr.io/x402-rs/x402-facilitator

Build Your Own

For custom facilitator implementations, see the Build Your Own Facilitator guide.

For full facilitator configuration and deployment details, see the x402-facilitator README.

Roadmap

Milestone	Description	Status
Facilitator for Base USDC	Payment verification and settlement service, enabling real-time pay-per-use transactions for Base chain.	✅ Complete
Metrics and Tracing	Expose OpenTelemetry metrics and structured tracing for observability, monitoring, and debugging	✅ Complete
Server Middleware	Provide ready-to-use integration for Rust web frameworks such as axum and tower.	✅ Complete
Client Library	Provide a lightweight Rust library for initiating and managing x402 payment flows from Rust clients.	✅ Complete
Solana Support	Support Solana chain.	✅ Complete
Protocol v2 Support	Support x402 protocol version 2 with improved payload structure.	✅ Complete
Multiple chains and multiple tokens	Support various tokens and EVM compatible chains.	✅ Complete
Axum Middleware v2 Support	Full x402 protocol v2 support in x402-axum with multi-chain, multi-scheme architecture.	✅ Complete
Reqwest Client v2 Support	Full x402 protocol v2 support in x402-reqwest with multi-chain, multi-scheme architecture.	✅ Complete
Build your own facilitator hooks	Pre/post hooks for analytics, access control, and auditability.	🔜 Planned
Bazaar Extension	Marketplace integration for discovering and purchasing x402-protected resources.	🔜 Planned
Gasless Approval Flow	Support for Permit2 and ERC20 approvals to enable gasless payment authorization.	🔜 Planned
Upto Scheme	Payment scheme supporting "up to" amount payments with flexible pricing.	🔜 Planned
Deferred Scheme	Payment scheme supporting deferred settlement and payment scheduling.	🔜 Planned

Related Resources

• x402 Protocol Documentation
• x402 Overview by Coinbase
• Facilitator Documentation by Coinbase

Contributions and Feedback

Feel free to open issues or pull requests to improve x402 support in the Rust ecosystem.

License

Apache-2.0