Crate r402_core 

r402-core

Core types, traits, and wire formats for the x402 payment protocol.

This crate is blockchain-agnostic. It defines the shared data model used by client, server, and facilitator implementations across every chain. Chain specific behavior lives in sibling crates (r402-evm, r402-svm).

Modules

• wire — On-the-wire JSON types (versioned: wire::v2)
• facilitator — Facilitator trait and DynFacilitator erasure
• scheme — Payment scheme registry and sealed builder traits
• hooks — Lifecycle hooks for verify/settle
• extensions — Extension framework for x402 protocol extensions
• payment — Payment<State> typestate for compile-time lifecycle safety
• chain — CAIP-2 chain identifiers, address, provider abstractions
• amount — Human-readable currency amount parsing ("$0.01" etc.)
• error — Layered error types (FacilitatorError, VerificationError, …)

Feature Flags

Flag	Default	Effect
telemetry		Enable tracing instrumentation
cache		Enable moka-backed TTL caches
ext-bazaar		Enable the bazaar resource discovery ext.
ext-payment-id		Enable the payment-identifier idempotency.
all-extensions		Enable every built-in extension
full		Enable every feature

License

Licensed under either of MIT or Apache-2.0, at your option.

Re-exports

pub use resource_server::ResourceServer;

pub use resource_server::WirePaymentPayload;

pub use error::ClientError;

pub use error::FacilitatorError;

pub use error::SettlementError;

pub use error::VerificationError;

pub use error_reason::AsPaymentProblem;

pub use error_reason::ErrorReason;

pub use error_reason::PaymentProblem;

pub use facilitator::BoxFuture;

pub use facilitator::DynFacilitator;

pub use facilitator::Facilitator;

pub use hooks::DynFacilitatorHooks;

pub use hooks::FacilitatorHooks;

pub use hooks::FailureRecovery;

pub use hooks::HookDecision;

pub use hooks::HookedFacilitator;

pub use hooks::SettleContext as HookSettleContext;

pub use hooks::VerifyContext as HookVerifyContext;

Modules

amount

Human-readable currency amount parsing.

cachecache

Shared cache primitives used by facilitator implementations.

chain

Blockchain-specific types and providers for x402 payment processing.

error

Layered error types for x402 facilitator operations.

error_reason

Machine-readable error codes used in x402 verify/settle responses.

extensions

Extension framework for x402 protocol extensions.

facilitator

Unified asynchronous interface for x402 payment facilitators.

hooks

Lifecycle hooks for facilitator verify / settle operations.

metricsmetrics

Stable metric names emitted by the r402 stack.

payment

Typestate lifecycle for a single x402 payment.

resource_server

Resource-server orchestration shared by HTTP and MCP transports.

scheme

Scheme identifiers, registry, and the extensible payment scheme system.

wire

On-the-wire JSON types for the x402 protocol.