Building a Paid API with x402: Accept USDC in 50 Lines

Building a Paid API with x402: Accept USDC in 50 Lines HTTP status 402 means "Payment Required." It's been reserved since 1997. Now it actually works. x402 is a protocol that lets any HTTP endpoint require on-chain payment before serving a response. Your server returns 402 with payment instructions, the client pays on Base, retries with a tx hash,...