# What Is the x402 Protocol? HTTP 402 Payments for AI Agents

DevFeed: [What Is the x402 Protocol? HTTP 402 Payments for AI Agents](<https://devfeed.tech/articles/what-is-the-x402-protocol-http-402-payments-for-ai-agents-10450.md>)

Original publisher: [Read original article](<https://dodopayments.com/blogs/x402-protocol/>)

Author: Ayush Agarwal

Published: 2026-09-08T00:00:00Z

Content type: tutorial

Language: en

Sources: [Dodo Payments Blog](<https://devfeed.tech/sources/dodo-payments-blog.md>)

Topics: [AI Agent](<https://devfeed.tech/topics/ai-agent.md>), [API](<https://devfeed.tech/topics/api.md>), [client](<https://devfeed.tech/topics/client.md>), [Model Context Protocol](<https://devfeed.tech/topics/model-context-protocol.md>)

Tags: [agent](<https://devfeed.tech/tags/agent.md>), [agents](<https://devfeed.tech/tags/agents.md>), [ai](<https://devfeed.tech/tags/ai.md>), [ai-agent](<https://devfeed.tech/tags/ai-agent.md>), [ai-agents](<https://devfeed.tech/tags/ai-agents.md>), [api](<https://devfeed.tech/tags/api.md>), [autonomous](<https://devfeed.tech/tags/autonomous.md>), [coinbase](<https://devfeed.tech/tags/coinbase.md>), [guide](<https://devfeed.tech/tags/guide.md>), [http](<https://devfeed.tech/tags/http.md>), [mcp](<https://devfeed.tech/tags/mcp.md>), [model-context-protocol](<https://devfeed.tech/tags/model-context-protocol.md>), [payments](<https://devfeed.tech/tags/payments.md>), [tools](<https://devfeed.tech/tags/tools.md>)

## AI overview

A technical guide to x402, an open payment standard that uses HTTP 402 to let clients pay for individual API requests without accounts, API keys, sessions, or subscriptions. It explains the payment handshake, the roles of clients, resource servers, and facilitators, plus x402's use over HTTP, MCP, and A2A transports.

## Source excerpt

A technical guide to the x402 protocol: how the HTTP 402 payment handshake works, the PAYMENT-REQUIRED and PAYMENT-SIGNATURE headers, facilitators, payment schemes, and where x402 fits next to card rails.