x402 Preflight
x402 Preflight: HTTP readiness check for x402 API buyers, sellers, and listing agents. It probes a target paid URL plus same-origin /.well-known/x402 and /openapi.json, /llms.txt, /agent-catalog.json, and /.well-known/ai-plugin.json, then returns payment-challenge signals, parsed payment metadata, comparable Bazaar resources, pricing context, discovery health, LLM/catalog readiness, conversion-readiness verdict, score, issues, and next actions. No payment is made to the target endpoint.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"input": {
"url": "Absolute public http(s) x402 endpoint URL to inspect; required to choose a target (the documented default is used if omitted)."
},
"price": "$0.001 USDC on Base",
"disclaimer": "No payment is made to the inspected target.",
"serviceName": "x402 Preflight",
"freePreviewUrl": "https://eveningdesk.cloud/token-signal/v1/x402-preflight?url=https%3A%2F%2Feveningdesk.cloud%2Ftoken-signal-x402%2Fv1%2Fx402-market-feed",
"returnedReadinessFields": [
"assessment.verdict",
"assessment.score",
"assessment.issues",
"assessment.nextActions",
"probes",
"paymentMetadata",
"marketContext"
]
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.001 USDC on Base to 0x1033…8129F. The signed payment is good for 5 minutes.
- Paid to
- 0x1033…8129F
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 1000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x10333d09dd1F5ebD8b8BD83f74A9d99C7b88129F",
"amount": "1000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"url": "https://76.13.79.47.nip.io/token-signal-x402/v1/x402-market-feed"
}
},
"output": {
"type": "json",
"example": {
"probes": {
"target": {
"status": 402
},
"llmsTxt": {
"status": 200
},
"openapi": {
"status": 200
},
"aiPlugin": {
"status": 200
},
"agentCatalog": {
"status": 200
},
"wellKnownX402": {
"status": 200
}
},
"assessment": {
"score": 90,
"issues": [
"No major preflight issues found in public HTTP checks."
],
"verdict": "healthy",
"nextActions": [
"Monitor external 402-to-settlement conversion."
]
},
"marketContext": {
"summary": {
"medianPriceUsdc": 0.001,
"pricedResources": 8,
"targetPriceVsMedian": "at-or-unknown"
}
},
"paymentMetadata": {
"network": "eip155:8453",
"amountUsdc": 0.001,
"serviceName": "x402 Market Feed"
}
}
},
"buyerUseCases": [
"Check whether a paid x402 endpoint is discoverable and returns usable payment metadata before buying.",
"Diagnose seller listing readiness without paying the target endpoint."
],
"freePreviewUrl": "https://76.13.79.47.nip.io/token-signal/v1/x402-preflight?url=https%3A%2F%2F76.13.79.47.nip.io%2Ftoken-signal-x402%2Fv1%2Fx402-market-feed"
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"queryParams"
],
"properties": {
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"type": "object",
"required": [
"url"
],
"properties": {
"url": {
"type": "string",
"format": "uri",
"description": "Absolute public http(s) x402 endpoint URL to inspect"
}
}
}
}
},
"output": {
"type": "object",
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
},
"routeTemplate": "/token-signal-x402/v1/x402-preflight"
}
}Provenance
- Seen in the source catalog
- 2026-08-27 21:51Z
- Last indexed by Roundhouse
- 2026-09-09 06:10Z
- Last enriched (probe, favicon, geo)
- 2026-09-12 10:45Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 16 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service x402 Preflight and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=x402%20Preflight' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://76.13.79.47.nip.io/token-signal-x402/v1/x402-preflight, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402, or use an organization key from https://roundhouseai.io/dashboard/team. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.