About vet402
vet402 buys from x402 sellers and publishes each result. As of 2026-11-07, 14,093 of its purchases had settled on-chain, and 12,858 of them counted as delivered. payOrRefuse, built on vet402, won a prize at ETHOnline 2026. vet402 was also selected for Circle's Arc Microgrants and for a Prezenti grant on Celo.
Who builds vet402
I'm Sen, and I build vet402 on my own. Elsewhere I go by Takeshi web3. The site is published by KIZUNA Creation, my sole proprietorship in Japan.
What vet402 does
An x402 payment proves that an agent paid. It does not show whether the seller delivered, so vet402 checks that by buying. I pay x402 sellers myself in stablecoins, check what each one sends back, and publish each purchase on the Impact page, including the ones that did not deliver. An agent can look up a seller before it pays.
Track record
Prezenti grant (Celo)
Prezenti, which funds projects built on Celo, selected vet402 for a grant to buy from and check the x402 sellers on Celo. Announced November 2026.
Circle Arc Microgrants
vet402 is one of 20 projects selected. Its project gives buyers a receipt for x402 purchases they pay through Circle Gateway (Circle's payment service) on Arc, Circle's blockchain. October 2026.
ETHOnline 2026, Bazantic prize
payOrRefuse, a check an agent runs on vet402 before it pays, won "Help an Agent Use Your Hackathon Project". September 2026.
NEAR Japan
From September 2019, before NEAR mainnet launched, I was a NEAR Ambassador and founded and ran NEAR Japan for about a year.
Background
Downloads
The @vet402/sdk package was downloaded 461 times from npm between 2026-10-08 and 2026-11-06 (npm downloads API, read 2026-11-07 14:44 UTC).
Data and code
The measurements are open data under CC BY 4.0 and the code is MIT. Read the state API, the methodology, or the code on GitHub.
Contact
Email support@vet402.com. On X, @vet402_com.
Operator details and the commercial-transactions disclosure are in the Legal Notice.