What problem does it solve? Building APIs that charge per request requires implementing the x402 payment protocol: returning 402 Payment Required responses, verifying X-PAYMENT headers, and settling Algorand transactions through a facilitator. This Skill provides the complete workflow for gating Express.js or Hono routes behind AVM payments without writing the protocol logic from scratch. ## Core Features & Use Cases - Payment Middleware Setup: Configure three middleware variants (paymentMiddlewareFromConfig, paymentMiddleware, paymentMiddlewareFromHTTPServer) to protect routes with per-endpoint USD pricing. - Multi-Network and Multi-Asset Support: Accept payments on Algorand testnet or mainnet, in ALGO or USDC ASA, and combine with EVM networks for cross-chain routes. - Facilitator and Paywall Servers: Run your own facilitator with an AVM signer, add browser paywall UI, dynamic pricing functions, and fee abstraction. - Use Case: You want to monetize a weather API. Apply the middleware with a route config mapping "GET /api/weather" to a $0.01 price, and unpaid callers receive a 402 response while paying callers pass through to the handler. ## Quick Start Ask the AI to create an Express server with x402 payment middleware protecting a GET /api/weather route at $0.01 paid to your Algorand testnet address.
