Market Data · x402 · early usage

Call before buying, swapping into or accepting any Base ERC-20, to learn if you can sel…

by tokencheck.402api.dev · discovered, not yet claimed by its owner · updated 2026-10-10

30d calls2

30d payers1

MethodGET

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

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.

Tags: token · base · honeypot · transfer-tax · liquidity · bazaar

Call contract

Method: GET
Input: query parameters
Output: json
Last paid call: 2026-10-10

Input example from Bazaar metadata

{
  "token": "0x940181a94A35A4569E4529A3CDfB74e38FD98631"
}

Output example

{
  "block": "52398867",
  "ethUsd": 2485.34437,
  "measuredAt": "2026-10-09T23:04:45.143Z",
  "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."
  ],
  "pools": [
    {
      "address": "0x6cDcb1C4A4D1C3C6d054b27AC5B77e89eAFb971d",
      "feePct": 0.3,
      "liquidityMethod": "2 × the pool's USDC balance (balanceOf at block 52398867); for concentrated-liquidity pools this counts all reserves, not in-range depth",
      "liquidityUsd": 43758468,
      "pairedWith": {
        "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "symbol": "USDC"
      },
      "sellable": {
        "amountIn": "27317.378708653002392855",
        "amountOut": "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)",
        "ok": true,
        "outUsd": 21791.869827
      },
      "source": "tracked by TradingLab",
      "transferTax": {
        "method": "TradingLab taxcheck job at 2026-10-08T20:25:52.000Z: receipts of the pool's 3 most recent swaps",
        "samples": [],
        "taxed": false
      },
      "venue": "aeroV2"
    },
    {
      "address": "0xbBf71AAD6E1F8D180D3B1D898528654c1d18b2fF",
      "feePct": 1,
      "liquidityMethod": "TradingLab registry estimate (pool added 2026-10-08, value refreshed by the registry job)",
      "liquidityUsd": 4664205,
      "pairedWith": {
        "address": "0x74ccbe53F77b08632ce0CB91D3A545bF6B8E0979",
        "symbol": "fBOMB"
      },
      "sellable": {
        "amountIn": "2857.2894550549357344",
        "amountOut": "103557.570587184740374855",
        "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)",
        "ok": true,
        "outUsd": null
      },
      "source": "tracked by TradingLab",
      "transferTax": {
        "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?",
        "samples": [
          "0x0bfd8e34e528e56ee56cd480722025c2f149d87152e1a6b2e209cc4b30f97b7d",
          "0x8ae22c6b10bdfd766ae7c09cc0c6ed2a55b001e4835524cd8e3597207f587608"
        ],
        "taxed": false
      },
      "venue": "aeroV2"
    }
  ],
  "poolsOmitted": 29,
  "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": {
    "bought": "31.120142866883571174",
    "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)",
    "ms": 503,
    "ok": true,
    "pool": "0x6cDcb1C4A4D1C3C6d054b27AC5B77e89eAFb971d",
    "receivedBack": "24.850225",
    "roundTripLossPct": 0.6,
    "spent": {
      "amount": "25",
      "symbol": "USDC",
      "usd": 25
    },
    "stage": "sell",
    "venue": "aeroV2"
  },
  "token": {
    "address": "0x940181a94A35A4569E4529A3CDfB74e38FD98631",
    "chain": "base",
    "decimals": 18,
    "method": "ERC-20 symbol()/name()/decimals()/totalSupply() eth_call at block 52398867",
    "name": "Aerodrome",
    "symbol": "AERO",
    "totalSupply": "1997645621.866174935169948746"
  },
  "verdict": "ok"
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/36445.json for the price and payment options.
Pay. Call GET https://tokencheck.402api.dev/v1/token-check. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.02 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 2 calls · 1 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.02	0x8C8A81E2acEc6ed62421f1f4E7125B0b84FFffdE	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x8C8A81E2acEc6ed62421f1f4E7125B0b84FFffdE",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "20000",
    "amountUsd": 0.02,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "oneOf": [
        {
          "description": "HTTP 200: the token report",
          "properties": {
            "block": {
              "type": "string"
            },
            "cached": {
              "type": "boolean"
            },
            "ethUsd": {
              "type": [
                "number",
                "null"
              ]
            },
            "measuredAt": {
              "type": "string"
            },
            "notes": {
              "items": {
                "type": "string"
              },
              "type": "array"
            },
            "pools": {
              "items": {
                "description": "venue, pairedWith, feePct, liquidityUsd, transferTax, sellable",
                "type": "object"
              },
              "type": "array"
            },
            "poolsOmitted": {
              "type": "integer"
            },
            "reasons": {
              "items": {
                "type": "string"
              },
              "type": "array"
            },
            "sellSimulation": {
              "description": "eth_simulateV1 buy-then-sell on the deepest pool: ok, roundTripLossPct, feesPct, error",
              "type": [
                "object",
                "null"
              ]
            },
            "token": {
              "type": "object"
            },
            "verdict": {
              "enum": [
                "ok",
                "caution",
                "avoid"
              ]
            }
          },
          "required": [
            "token",
            "verdict",
            "reasons",
            "pools",
            "measuredAt"
          ],
          "type": "object"
        },
        {
          "description": "Error body. HTTP 400 = bad or missing input; HTTP 503 = check failed or timed out (25 s). The payment is not settled on errors, so the caller is not charged.",
          "example": {
            "error": "query parameter `token` must be a 0x-prefixed 40-hex-digit Base token address"
          },
          "properties": {
            "error": {
              "description": "What went wrong, in plain words",
              "type": "string"
            }
          },
          "required": [
            "error"
          ],
          "type": "object"
        }
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://tokencheck.402api.dev/v1/token-check"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://tokencheck.402api.dev/v1/token-check");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://tokencheck.402api.dev/v1/token-check")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: tokencheck.402api.dev
Endpoint: https://tokencheck.402api.dev/v1/token-check
Machine-readable: /resources/36445.json