x402 answers and agent discovery guides
Plain answers to common x402 questions, and guides that connect discovery to a usable tool, a free check and an explicit purchase decision. Each page states its sources and limits.
Choose your workflow
Publish an x402 API profile with a readiness report and badge
Prepare your x402 API for agent discovery: validate free, inspect readiness evidence, then publish an Ontario service profile for 0.50 USDC only when you need it.
MCP Registry, Smithery or Bazaar: build the agent purchase path
Separate MCP installation from paid API discovery. Give agents a callable tool, free preflight, explicit payment requirements and evidence of fulfilled output.
Can x402 payments be refunded?
An x402 payment is a USDC transfer that is final once it settles, so a refund is a voluntary new transfer and the real protection is a seller that settles after the result exists.
How big is the x402 market?
Coinbase's Bazaar index lists tens of thousands of paid endpoints, but most show one or two payers in 30 days, and repeat demand sits in a few categories.
Are cheaper x402 APIs worse?
Not necessarily; price rarely decides which x402 API agents use, as a reseller that charges more than the original search API and gets more calls shows.
Do Claude or ChatGPT pay for MCP tools?
Claude and ChatGPT can call MCP tools, but neither pays for one by itself; a paid MCP tool needs a client wrapper with a funded wallet and a spending limit.
Which networks does x402 support?
x402 is network-agnostic; Coinbase's facilitator settles on Base, Solana, Polygon, Arbitrum, Monad and World, and most paid traffic today is USDC on Base.
How do I get my API discovered by AI agents?
Agents search indexes rather than browse websites, so an API is found through Coinbase's Bazaar, x402scan and directories, and through a description that names the task.
How do I know an x402 endpoint is legit?
Three observable checks show whether an unknown x402 endpoint is live, priced as listed and used by repeat buyers; Ontario's finder runs them for 0.005 USDC.