Crate r402_evm 

EIP-155 (EVM) chain support for the x402 payment protocol.

This crate provides implementations of the x402 payment protocol for EVM chains with the “exact” payment scheme based on ERC-3009 transferWithAuthorization.

Features

• CAIP-2 Addressing: Uses CAIP-2 chain IDs (e.g., eip155:8453) for chain identification
• ERC-3009 Payments: Gasless token transfers using transferWithAuthorization
• Smart Wallet Support: EIP-1271 for deployed wallets, EIP-6492 for counterfactual wallets
• Multiple Signers: Round-robin signer selection for load distribution
• Nonce Management: Automatic nonce tracking with pending transaction awareness

Architecture

The crate is organized into several modules:

• chain - Core EVM chain types, providers, and configuration
• exact - EIP-155 “exact” payment scheme

Feature Flags

• server - Server-side price tag generation
• client - Client-side payment signing
• facilitator - Facilitator-side payment verification and settlement
• telemetry - OpenTelemetry tracing support

Re-exports

pub use exact::Eip155Exact;

pub use exact::client::Eip155ExactClient;client

pub use exact::client::Eip155ExactClientBuilder;client

pub use exact::client::Permit2Approver;client

Modules

chain

EVM chain support for x402 payments via EIP-155.

exact

EIP-155 “exact” payment scheme implementation.

Structs

USDC

Ergonomic accessors for USDC token deployments on well-known EVM chains.

USDM

Ergonomic accessors for USDM (MegaUSD) token deployments on EVM chains.

Statics

EVM_NETWORKS

Well-known EVM (EIP-155) networks with their names and CAIP-2 identifiers.

Functions

usdc_evm_deployment

Returns the USDC deployment for a specific EVM chain, if known.

usdc_evm_deployments

Returns all known USDC deployments on EVM chains.

usdm_evm_deployment

Returns the USDM deployment for a specific EVM chain, if known.

usdm_evm_deployments

Returns all known USDM deployments on EVM chains.