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

Описание и применение

Рецепт показывает, как использовать статус‑код 402 x402 для микроплатежей в HTTP‑навигации, позволяя автономным AI‑агентам оплачивать сервисы без сторонних SDK.

Задача

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.

Результат

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.

Рабочий процесс

• 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.

Доказательства

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

Источник

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.

Источник