Call before paying an unfamiliar x402 endpoint, or to pick between providers
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.
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://tokencheck.402api.dev/v1/seller-check
| Category | Market data |
|---|---|
| Provider host | tokencheck.402api.dev |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 0 from 0 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-10 | valid payment request | 402 | $0.02 | 1483 ms |
Example input (from the provider)
{
"discoverable": true,
"method": "GET",
"queryParams": {
"url": "https://tokencheck.402api.dev/v1/token-check"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"discoverable": {
"const": true
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"payTo": {
"description": "A seller's Base payTo address (reputation + its most-called Bazaar resource is probed). Give this or url.",
"pattern": "^0x[0-9a-fA-F]{40}$",
"type": "string"
},
"url": {
"description": "The x402 resource URL you are about to pay (http/https). Give this or payTo.",
"maxLength": 2048,
"pattern": "^https?://",
"type": "string"
}
},
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"oneOf": [
{
"description": "HTTP 200: the seller report",
"properties": {
"bazaar": {
"description": "listed, listing (description, amount, 30-day calls/payers), other listings for the payTo",
"type": "object"
},
"cached": {
"type": "boolean"
},
"index": {
"type": "object"
},
"measuredAt": {
"type": "string"
},
"notes": {
"items": {
"type": "string"
},
"type": "array"
},
"payTo": {
"type": [
"string",
"null"
]
},
"probe": {
"description": "status, ms, tls, x402 (version, valid, accepts with recognised asset, usd, payTo)",
"type": [
"object",
"null"
]
},
"query": {
"type": "object"
},
"reasons": {
"items": {
"type": "string"
},
"type": "array"
},
"reputation": {
"description": "last24h / last7d: payments, distinctPayers, totalUsd, medianUsd, topPayerShare, complete",
"type": [
"object",
"null"
]
},
"verdict": {
"enum": [
"looks legit",
"caution",
"avoid"
]
}
},
"required": [
"verdict",
"reasons",
"bazaar",
"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"
}
},
"required": [
"input"
],
"type": "object"
}