Frequently Asked Questions
Everything you need to know about the x402 protocol.
What is x402?
x402 is an open payment protocol that embeds payment negotiation into HTTP using the 402 status code. It enables instant, permissionless payments for web resources.
How does x402 work?
When a client requests a paid resource, the server replies with HTTP 402 and payment details. The client signs a payment payload and resubmits the request with an X-PAYMENT header. The server verifies and settles the payment before returning HTTP 200.
Which tokens are supported?
Currently, stablecoins that implement EIP-3009 are supported (e.g., USDC on Base). Support for other tokens is limited but expanding.
Does x402 charge fees?
The protocol itself has no fees. However, on-chain transactions incur network fees (gas), and facilitators may charge a service fee.
Can AI agents use x402?
Yes. A core goal of x402 is enabling AI agents to pay for data and services autonomously without human intervention.
Is x402 secure?
Payments are cryptographically signed using EIP-3009, and no account details are exposed. It leverages the security of the underlying blockchain.