# x402: HTTP 402 finally used

x402 revives the dormant ‘402 Payment Required’ status code: your endpoint answers an unpaid request with the exact price, asset, and pay-to address; the agent pays and retries with proof. Payments become a normal part of an API call.

Canonical: https://robauto.ai/learn/agentic-commerce-101/4

_Agentic Commerce 101: How Agents Buy and Sell — lesson 4 of 20 (DEFINITION)_

x402 revives the dormant ‘402 Payment Required’ status code: your endpoint answers an unpaid request with the exact price, asset, and pay-to address; the agent pays and retries with proof. Payments become a normal part of an API call.

Source: [x402 open standard](https://www.x402.org?utm_source=robauto)

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