Build an x402 Payment Server

Create an Express server that charges USDC for API access using the x402 payment protocol. Callers pay per-request in USDC on Base — no accounts, API keys, or subscriptions needed.

How It Works

x402 is an HTTP-native payment protocol. When a client hits a protected endpoint without paying, the server returns HTTP 402 with payment requirements. The client signs a USDC payment and retries with a payment header. The facilitator verifies and settles the payment, and the server returns the response.

Confirm wallet is initialized and authed

npx awal@latest status

If the wallet is not authenticated, refer to the authenticate-wallet skill.

Step 1: Get the Payment Address

Run this to get the wallet address that will receive payments: