HTTP 402 is not reserved for future use anymore: I put a 1-cent paywall on a live API for AI agents

说明与用途

文章介绍了使用 HTTP 402 和 x402 协议实现的 1 美分付费墙，允许 AI 代理在无需注册或密钥的情况下使用 Base 网络的稳定币支付一次性 API 调用。

问题

Traditional API key models require onboarding and are unsuitable for one‑off AI agent requests, leading to missed payments and high friction.

结果

A live API now accepts 1‑cent payments via stablecoin, eliminating onboarding, chargebacks, and merchant identity requirements, making it viable for small operators and AI agents.

工作流

• 1. Agent sends request to endpoint without payment header.
• 2. Server responds 402 with x402 challenge body (payment requirements).
• 3. Agent signs EIP‑712 authorization for exact amount and retries with X‑PAYMENT header.
• 4. Server verifies signature via facilitator, settles stablecoin transfer, and returns JSON result.

证据

The challenge is public, the paid call costs one cent, and the data behind it is a free CC BY 4.0 dataset.

来源

An agent reads accepts, signs an EIP‑712 authorization for exactly that amount, retries with an X‑PAYMENT header, and gets the JSON.

来源