x402 preflight / reputation — verify BEFORE you pay
x402 preflight / reputation — verify BEFORE you pay. Give it an x402 endpoint_url (or a payTo address) and it returns, in one cheap deterministic call: is the resource reachable, is it present in the CDP Bazaar discovery catalog (serviceName, declared payTo, price, network, tags, last_seen), and — the key integrity check — does the payTo the endpoint actually demands in its live HTTP 402 challenge MATCH the payTo the catalog advertises (payTo_match). It runs a keyless HEAD/OPTIONS/402 probe that never moves funds, extracts the real payTo/amount/asset/network from the challenge, scores listing freshness, and — if you pass a prev snapshot {payTo,amount,lastUpdated} — flags whether the endpoint changed since you last saw it (anti-rug). Output is a 0-100 scorecard + letter grade + reason codes + an actionable verdict (pay_ok / caution / do_not_pay). For any router, wallet agent or M2M client that pays third-party x402 endpoints and needs to avoid paying a hijacked, dead, or repriced resource. Deterministic, no LLM, Ed25519-signed. 0.01 USDC via x402 on Base. SYNTHORA.
Provider
x402meta.hergertsynthora.com · discovered, not yet claimed by its owner
Payment (x402 accepts[])
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0x6D9F318463168fF637b50E5b9a21392e97c7c167",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "10000",
"maxTimeoutSeconds": 300
}
]Output schema
{
"bazaar": {
"info": {
"input": {
"body": {
"endpoint_url": "https://api.exa.ai/search"
},
"bodyType": "json",
"method": "POST",
"type": "http"
},
"output": {
"example": {
"niche": "x402meta",
"ok": true,
"result": {
"catalog": {
"amount": "7000",
"last_seen": "2026-07-07T21:49:52.202Z",
"matched_by": "endpoint",
"network": "eip155:8453",
"payTo": "0x6d6E695b09861467c7d462f5AAF31cF3540B9192",
"resource": "https://api.exa.ai/search",
"serviceName": "exa-search"
},
"changed": null,
"endpoint_url": "https://api.exa.ai/search",
"final_status": 402,
"host": "api.exa.ai",
"in_catalog": true,
"live_challenge": {
"amount": "7000",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"network": "eip155:8453",
"payTo": "0x6d6E695b09861467c7d462f5AAF31cF3540B9192"
},
"payTo": "0x6d6e695b09861467c7d462f5aaf31cf3540b9192",
"payTo_declared": "0x6d6e695b09861467c7d462f5aaf31cf3540b9192",
"payTo_live": "0x6d6e695b09861467c7d462f5aaf31cf3540b9192",
"payTo_match": true,
"reachable": true,
"requires_payment": true,
"scorecard": {
"challenge_wellformed": true,
"changed": null,
"grade": "B",
"in_catalog": true,
"listing_age_days": 1,
"payTo_match": true,
"reachable": true,
"reason_codes": [
"reachable",
"in_catalog",
"emits_402",
"payto_match",
"challenge_wellformed",
"listing_fresh"
],
"requires_payment": true,
"score": 88
},
"service_version": "1.0",
"signed": true,
"verdict": "pay_ok"
}
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"anyOf": [
{
"required": [
"endpoint_url"
]
},
{
"required": [
"payTo"
]
}
],
"properties": {
"endpoint_url": {
"description": "The x402 endpoint URL to preflight (http/https). Either this or payTo is required.",
"type": "string"
},
"payTo": {
"description": "A payTo address (0x…40hex) to look up in the catalog instead of / in addition to a URL.",
"type": "string"
},
"prev": {
"description": "Optional prior snapshot to detect change (anti-rug).",
"properties": {
"amount": {
"type": "string"
},
"lastUpdated": {
"type": "string"
},
"payTo": {
"type": "string"
}
},
"type": "object"
}
},
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST",
"PUT",
"PATCH"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"niche": {
"type": "string"
},
"ok": {
"type": "boolean"
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
}Use it
curl
curl "https://x402meta.hergertsynthora.com/service" # -> 402 Payment Required, accepts[] lists how to pay # retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://x402meta.hergertsynthora.com/service");
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://x402meta.hergertsynthora.com/service")
if res.status_code == 402:
accepts = res.json()["accepts"]
# pay one of accepts[] via an x402 client, then retry with the payment headerMachine-readable
Everything on this page is also available as clean JSON at /resources/8720.json, and this resource appears in /discovery/resources and /discovery/search.