x402 Quick Start

x402 is an HTTP payment protocol. When a client requests a gated endpoint, the server returns a 402 Payment Required response containing the payment terms: USDC amount, destination wallet address, and network (Base or Solana).

The client pays on-chain, submits proof to a facilitator, and retries the request with a payment token in the header. The server verifies and responds with 200.

The handshake has five steps. This skill walks your agent through each one: parse the 402 response fields, display them for operator review, construct the payment submission, retrieve the payment token from the facilitator, and format the retry request. Every step is documented with exact field names and decision rules, including what to do when the facilitator's scheme differs from the standard pattern.

This skill is the entry point for working with x402. It covers the payment pattern only. For monitoring revenue across x402 endpoints (USDC totals, success rates, payer patterns, pricing optimization), see x402 Revenue Dashboard ($29 on ClawMart). For building multi-step data pipelines through x402-gated sources, see Data Pipeline Builder ($89 on ClawMart).