35 x402 hosts served no signed offer. Here is how to check yours in one request.

The useful part

In August I pointed a free checker at every host on the public x402 discovery list. x402 is the HTTP 402 payment flow Coinbase and Cloudflare revived for agents: request a resource, get a 402 with the price and the address, pay, retry. What it does not do, by default, is commit the seller to anything before the money moves.

How it works

• If the price changes between the challenge and the settlement, or the payTo address was swapped by whoever sits between you and the origin, the buyer finds out after paying, if at all.
• The x402 spec has an extension for exactly this: signed offers and signed receipts.
• A buyer holds a commitment it can check before paying, against a key anyone can fetch, without asking the seller.
• On 2026-08-03 I sent one GET to every host on the public x402 discovery list, 35 hosts, and read the 402 each one returned.

Details worth keeping

I run an x402 store where the customers are AI agents. Thousands of settlements a day go through it. The 402 says "this costs $0.01, pay here." Nobody signed that.