x402dir.com
What is a x402 Facilitator?
How facilitators verify payments and settle on-chain for AI agents and apps.
Overview
When an AI agent pays for a service using the x402 protocol, a facilitator handles the payment verification and blockchain settlement. Think of it like a payment processor — you don't interact with the bank directly, the processor handles it.
Different facilitators charge different fees and support different blockchain networks. Most are free, some charge a percentage per transaction, and others use variable pricing.
How it works
The x402 protocol uses HTTP status code 402 (Payment Required) to enable machine-to-machine payments. When an AI agent encounters a 402 response, it knows it needs to pay — and the facilitator is the service that makes that payment happen on-chain.
Sellers advertise a price and receiving wallet. Buyers (or agents) sign a payment, the facilitator verifies and settles USDC (or other supported assets), and the API returns the paid response.
Fees & chains
Facilitators differ in the chains they support (Base, Ethereum, Solana, Polygon, and more), the tokens they accept (primarily USDC), their fee structures, and whether they're open source or self-hostable.
Use the cost calculator and recommendation tools on this site to compare options against your expected volume and chain.
This directory
This directory tracks 20+ facilitators across 10+ chains to help developers and AI agents find the best option for their use case.
x402dir is a public comparison surface — not a facilitator itself. For the protocol homepage and docs, see x402.org.
Frequently Asked Questions
What is an x402 facilitator?
An x402 facilitator is a service that verifies and settles on-chain payments on behalf of buyers and sellers using the x402 protocol. It handles the blockchain transaction so your app or AI agent doesn’t have to.
How do x402 payments work?
When a client sends a request to an x402-enabled API, the server responds with HTTP 402 (Payment Required) and a price. The client signs a payment, the facilitator verifies and settles it on-chain, and the server returns the paid content.
Which blockchains are supported?
Most facilitators support Base and Ethereum. Many also support Solana, Polygon, Arbitrum, and other EVM-compatible chains. This directory tracks chain support for every facilitator.
How do I choose a facilitator?
Compare fees, supported chains, and whether the facilitator is open source or self-hostable. Use the cost calculator and recommendation tools on this site to find the best fit for your volume and chain.