AI agents pay for APIs on their own. vet402 buys x402 APIs and publishes whether each paid answer arrived, failures included. Free to read.
Japan
Joined January 2023
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Before paying $0.03 to screen 10 tokens, see what this seller's cheaper calls returned.
Oct 6 to 17 UTC, vet402 paid 4 of its 9 @Base listings (gas, facts, basename, wallet) at 0.001 to 0.005 USDC.
All 4 settled and returned the declared keys.
/v1/batch wasn't one. Small sample.
Screening many new Base tokens? One call to POST /v1/batch checks up to 10 for $0.03 USDC (x402): buy tax, sell tax and round-trip loss per token, simulated in eth_call, nothing traded. Facts, not advice. base-facts.yankii.fr
The record for one of the 7, with the declared price and payee: vet402.com/observatory/e/d21…
A catalog where AI agents shop for paid APIs passed 100,000 listings.
@Coinbase's x402 Bazaar: 100,199 on Oct 30 UTC.
A listing is a claim. Since Aug 14, vet402 paid 7,435 endpoints across catalogs. 6,888 sent a 2xx body at least once.
Most misses were 4xx, maybe vet402's fault.
Coinbase's count is pagination.total here
(live, so it moves): api.cdp.coinbase.com/platfor…
vet402's counts are the rows "Endpoints with at least one settled receipt" and "...delivered response"
(2xx other than 202, body not empty): vet402.com/observatory/state
Payment terms an agent can read are half of it.
The other half is what the answer should look like.
Aug 14 to Oct 29 UTC, 11,056 of vet402's settled buys answered 200. 6,567 came from listings that declare no output shape.
Maybe fine. vet402 has nothing to check them against.
Built to be used by software, not just read by people.
One URL connects any MCP client. A full API with payment terms an agent can read on its own. x402 pay-per-call in USDG.
Everything an agent needs to call Actuary without a human in the loop.
actuaryai.pro/docs
How vet402 checks a paid answer against the declared output, and what no_declaration means: vet402.com/observatory/metho…
vet402 bought x402 APIs on @Arbitrum for five days.
One failed call cost money.
Oct 22 to 26 UTC: 117 tries at 30 hosts. 62 settled, 61 got a 200. 50 stopped before USDC moved, 44 a 4xx when vet402 sent no input.
5 answered but no transfer was found.
Paying for one article only works if the article arrives.
By Oct 29, 12,088 paid API calls I made settled on-chain.
10,958 returned content.
Of the other 1,130, 696 got a 4xx that may be my fault.
434 got a 5xx, a 202, an empty body or no status logged.
vet402.com/observatory/state #x402 @Base
900K+ x402 payments on Celo.
I wanted to know what comes back after one.
Oct 11-28, vet402 bought Celo listings on CDP Bazaar with its own USDC. 209 settled, 204 came back with content.
50 never settled, so no USDC moved.
164 of the 209 hit one host.
vet402.com/x402/chains
Btw, I gonna go to Mumbai next week!
See you and let's enjoy creating the future.
#ETHGlobal #Devcon #x402 🇮🇳
AI agents now pay sellers they have never met.
Has anyone paid this one before?
Since Aug 14 UTC vet402 paid 6,985 x402 endpoints, settled on chain. 6,501 delivered at least once.
Some of the other 484 failed on vet402's own requests.
One buyer's record: vet402.com/observatory
Three in four x402 listings that take Circle Gateway on Arc are missing from CDP Bazaar.
Oct 26 UTC: 2,035 of 2,728 active Gateway listings on Arc are only in Circle's x402 discovery, all from 6 hosts.
CDP Bazaar lists the other 693, from 17 hosts.
vet402 reads both. @circle
No signup also means no account to ask.
The agent's own record is the receipt.
On Solana since Aug 21 UTC, vet402 settled 793 x402 buys. 752 delivered. 41 got a 4xx after paying, which can be vet402's own request.
Agents: log what you paid for.
86% is a number worth publishing.
The next step is splitting the other 14% by who caused it.
vet402's paid x402 buys, Sep 26 to Oct 26 UTC:
7,004 settled, 6,519 (93%) got a 2xx.
Of the 485 misses, 288 were a 4xx that can be vet402's own request, 134 no reply by 20 s, 63 a 5xx.
Celo settles around the clock. Agent sellers there are few.
1,695 active x402 listings accept Celo, from 16 hosts (Oct 26 UTC). vet402 had tried 5.
Oct 26: 9 calls at 6 new hosts.
All 9 failed before any @USDC moved: each 402 reply carried a facilitator 401, "Missing X-API-Key".
Every x402 count, vet402's included, starts from what public catalogs list.
On Oct 22, CDP Bazaar alone listed 28,423 resources from 2,712 hosts. A seller whose facilitator lists elsewhere is outside that count.
A small number for a chain is a coverage limit, not a verdict.
901 x402 listings accept Robinhood Chain.
Not one lists it first.
In all 901, Base comes before it.
vet402 has no purchase lane on Robinhood Chain, so none of those 901 has a measured paid answer there.
Accepting a chain is not settling on it.
Identity says which agent paid.
Permissions say it was allowed to.
Audit needs one more line: did the paid call answer?
vet402 keeps that line per purchase on 8 chains.
Since Aug 14: 10,687 settled, 9,722 answered 2xx with a body, 662 got a 4xx that may be vet402's own request.
Thanks @circle.
vet402 was selected for one of 20 Arc Microgrants : buyer-side receipts for x402 purchases settled through Circle Gateway on @Arc.
Arc: 158 attempts, 76 settled, all 76 got 2xx.
25 of the other 82 are inconclusive (2026-10-24).
dorahacks.io/hackathon/arc-m…
