v0.0.19

What's new

x402 Payment Protocol

• createFacilitatorClient() — client for payment verification and on-chain settlement
• createMemoryX402SessionStore() — in-memory pay-once session store
• encodeX402Header() / decodeX402Header() — Base64 header encoding
• processX402Payment() — verify + settle pipeline

Middleware x402 Support

All four framework wrappers now accept an optional x402 config:

• Express: siwaMiddleware({ x402 }) + siwaCors({ x402: true })
• Next.js: withSiwa(handler, { x402 }) + siwaOptions({ x402: true })
• Hono: siwaMiddleware({ x402 }) + siwaCors({ x402: true })
• Fastify: siwaAuth({ x402 }) + siwaPlugin({ x402: true })

Pay-Once Sessions (SIWX)

• Sessions keyed by (address, resource.url) for route isolation
• Configurable TTL with pluggable X402SessionStore interface
• First request requires payment; subsequent requests pass through

Types

• X402Config, PaymentRequirements, PaymentPayload, PaymentRequired
• X402Payment, FacilitatorClient, X402SessionStore, X402Session