x402 Explained: HTTP‑Native Micropayments for AI Agents (With Real Code)

说明与用途

该配方演示了如何使用 402 x402 状态码进行 HTTP 原生微支付，使自主 AI 代理能够在不使用自定义 SDK 的情况下为服务付费。

问题

Developers building autonomous AI agents need a lightweight, HTTP‑native way to charge or pay for on‑the‑fly services without custom SDKs or websockets.

结果

The recipe demonstrates a complete, HTTP‑native micropayment flow using x402, enabling AI agents to pay for services on‑the‑fly with minimal client changes.

工作流

• 1. Agent sends request to protected endpoint (e.g., GET /summarize).
• 2. Server responds with 402 Payment Required and JSON body containing payment request (x402).
• 3. Agent builds ERC‑20 approve/transferFrom transaction (or uses meta‑transaction relayer) to pay the specified amount to the server’s treasury address.
• 4. Agent signs the nonce/timestamp payload with its private key.
• 5. Agent re‑sends original request, adding X-Payment header with the signature.
• 6. Server verifies signature, checks nonce validity, confirms on‑chain transfer, and processes the request, returning 200 OK.

证据

When a server returns 402 Payment Required and a JSON body containing the payment request.

来源

Agent builds an ERC‑20 approve + transferFrom transaction (or uses a meta‑transaction relayer) to pay the exact amount to the server’s treasury address.

来源