{"service":"402api checks","description":"Two pay-per-call checks: $0.02 USDC each on Base to 0x8C8A81E2acEc6ed62421f1f4E7125B0b84FFffdE via x402 v2. Call without payment to get the 402 PAYMENT-REQUIRED header, sign it with any x402 v2 client (e.g. @x402/fetch), retry with PAYMENT-SIGNATURE. Errors (400/503) are JSON {error} and not charged.","endpoints":{"tokenCheck":"GET /v1/token-check?token=0x... — Call before buying, swapping into or accepting any Base ERC-20, to learn if you can sell it back. $0.02, ~1-3 s, measured on-chain: honeypot test (simulated buy then sell via the deepest pool: sell ok? round-trip loss vs fees), per-pool transfer tax from real recent swap receipts, USD liquidity per pool (Uniswap v2/v3, Aerodrome, Slipstream), sell quotes, and an ok/caution/avoid verdict citing each fact. Errors: 400/503 JSON {error}, not charged.","sellerCheck":"GET /v1/seller-check?url=<x402 resource URL> | ?payTo=0x... — Call before paying an unfamiliar x402 endpoint, or to pick between providers. $0.02, usually <1 s plus one probe: live unpaid probe (status, latency, TLS, PAYMENT-REQUIRED decoded and sanity-checked), seller reputation from indexed on-chain USDC payments to its Base payTo (24 h/7 d count, distinct payers, total and median USD, top-payer share), Bazaar listing and price, and a looks legit/caution/avoid verdict citing each fact. Errors: 400/503 JSON {error}, not charged.","health":"GET /v1/health","openapi":"GET /openapi.json","wellKnown":"GET /.well-known/x402","llms":"GET /llms.txt"},"price":{"amount":"20000","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","network":"eip155:8453"},"example":{"request":"GET /v1/token-check?token=0x940181a94A35A4569E4529A3CDfB74e38FD98631","response":{"token":{"address":"0x940181a94A35A4569E4529A3CDfB74e38FD98631","chain":"base","symbol":"AERO","name":"Aerodrome","decimals":18,"totalSupply":"1997645621.866174935169948746","method":"ERC-20 symbol()/name()/decimals()/totalSupply() eth_call at block 52398867"},"verdict":"ok","reasons":["Total measured liquidity $66,630,326 across 10 pool(s).","Sell quote succeeded on all 6 pool(s) checked.","No transfer tax seen in recent swaps on 5 pool(s).","Simulated $25 buy then full sell on the aeroV2 USDC pool lost 0.6% (pool fees account for 0.6%): sells work and no meaningful tax."],"sellSimulation":{"pool":"0x6cDcb1C4A4D1C3C6d054b27AC5B77e89eAFb971d","venue":"aeroV2","spent":{"symbol":"USDC","amount":"25","usd":25},"feesPct":0.6,"method":"eth_simulateV1 at block 52398867: a fresh address funded by state override spends 25 USDC buying through aeroV2 router 0xcF77a3Ba9A5CA399B7c97c74d54e5b1Beb874E43, then sells every token it received back into the same pool (nothing is signed or broadcast)","ok":true,"stage":"sell","bought":"31.120142866883571174","receivedBack":"24.850225","roundTripLossPct":0.6,"ms":503},"pools":[{"address":"0x6cDcb1C4A4D1C3C6d054b27AC5B77e89eAFb971d","venue":"aeroV2","pairedWith":{"symbol":"USDC","address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"},"feePct":0.3,"source":"tracked by 402api","liquidityUsd":43758468,"liquidityMethod":"2 × the pool's USDC balance (balanceOf at block 52398867); for concentrated-liquidity pools this counts all reserves, not in-range depth","transferTax":{"taxed":false,"samples":[],"method":"402api taxcheck job at 2026-10-08T20:25:52.000Z: receipts of the pool's 3 most recent swaps"},"sellable":{"ok":true,"amountIn":"27317.378708653002392855","amountOut":"21791.869827","outUsd":21791.869827,"method":"on-chain quoter/reserves eth_call selling 0.1% of the pool's token balance into this pool (does not detect wallet-level transfer blocks or the tax itself)"}},{"address":"0xbBf71AAD6E1F8D180D3B1D898528654c1d18b2fF","venue":"aeroV2","pairedWith":{"symbol":"fBOMB","address":"0x74ccbe53F77b08632ce0CB91D3A545bF6B8E0979"},"feePct":1,"source":"tracked by 402api","liquidityUsd":4664205,"liquidityMethod":"402api registry estimate (pool added 2026-10-08, value refreshed by the registry job)","transferTax":{"taxed":false,"samples":["0x0bfd8e34e528e56ee56cd480722025c2f149d87152e1a6b2e209cc4b30f97b7d","0x8ae22c6b10bdfd766ae7c09cc0c6ed2a55b001e4835524cd8e3597207f587608"],"method":"receipts of the pool's 2 most recent swap(s) found by eth_getLogs (Swap event) over the last 500 blocks: does part of a AERO transfer out of / payment into the pool go to the token contract or a burn address?"},"sellable":{"ok":true,"amountIn":"2857.2894550549357344","amountOut":"103557.570587184740374855","outUsd":null,"method":"on-chain quoter/reserves eth_call selling 0.1% of the pool's token balance into this pool (does not detect wallet-level transfer blocks or the tax itself)"}}],"poolsOmitted":29,"ethUsd":2485.34437,"measuredAt":"2026-10-09T23:04:45.143Z","block":"52398867","notes":["16 smaller pool(s) omitted.","5 pool(s) with under $1,000 measured liquidity omitted.","Measured facts, not advice. The simulated sell shows a fresh wallet can sell right now; owner-changeable taxes, blacklists or trading switches can still change later."]}}}