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x402 Checker — Batch URL 402 Probe
x402
x402 Checker — Batch URL 402 Probe is a paid API for AI agents from x402-checker.nock-for-mak.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Checks up to 10 URLs in one call to detect x402 payment-gating, extract payment details, and surface risk flags before any USDC is spent.
Price / call$0.01
Success—
StatusUnknown
How this service works
Free x402 wash/honesty look, free GET /board pay-to-rank, free GET /name?n= ENS-style agent name lookup, $0.05 USDC POST /name (30 day TTL) and POST /bid (adds to 24h total) and /report, $0.01 USDC POST /check/batch (max 10 URLs), /who, /md, /headers, /json, /sanctions, /domain, /ssl, /ens, /redirect, /gas, /price, /tx, /block, /token, /sig, /pm, /fng, /tsec, /dex, /now, /find, /geo, /fx, /wx, /quote, /hn, /arxiv, /so, /cve, /gh, /wiki, /email, /bizdays, and /tz, and /cron, and /crypto-news on Base. GET /check stays free for one URL. Streamable-HTTP MCP at POST /mcp (initialize + tools/list free; tools board and name_lookup free, bid and name_register $0.05). Crawler files: GET /llms.txt and GET /.well-known/agent.json (also agent-card.json). /headers is a raw header dump. /json validates JSON against a JSON Schema. /sanctions is an OFAC SDN digital-currency screen. /domain is a DNS/RDAP/TLS dossier. /ssl is TLS cert facts from public CT plus a live HTTPS HEAD. /ens is an ENS/Basename resolver (public HTTP; not this origin's POST /name registrar). /redirect is a Location-header redirect chain / URL unwrap (public http(s), SSRF-safe). /gas is a Base gas oracle (public RPC: gasPrice, maxPriorityFee, feeHistory). /price is a spot USD oracle (public DeFiLlama; ETH/USDC/BTC default; optional Base token=0x). /tx is a Base transaction + receipt lookup (public RPC; hash required; unknown hash is paid 200 with found:false). /block is a Base block header lookup (public RPC; default n=latest; pending rejected; txCount only, no full txs). /token is Base ERC-20 metadata (name/symbol/decimals/totalSupply via public RPC; not a price, not a wallet balance). /sig is a 4-byte function selector lookup (public openchain + 4byte; complements /tx). /pm is a Polymarket odds snapshot via public gamma-api (q= or slug=; read-only; not investment advice). /fng is the Crypto Fear & Greed Index via public alternative.me (optional limit=1..30; not investment advice). /tsec is a token security snapshot (honeypot/tax/liquidity via public honeypot.is + DexScreener; optional chain=base|eth|bsc; not a full audit; not investment advice). /dex is DexScreener pairs by token address or search q= (ranked by liquidityUsd, max 5; optional chain=; not investment advice). /now is a UTC clock (unix, ms, iso; alias /time; no params; for IANA zones use /tz). /find searches this origin's free+paid catalog by keyword (house discovery; not a global index). /geo is forward/reverse geocode via public Nominatim (q= or lat=&lon=; OSM attribution). /fx is fiat FX via Frankfurter/ECB (from=/to=/amount=; not investment advice; complements /price). /wx is current weather via public Open-Meteo (q= or lat=&lon=; units=metric|us). /quote is equity/index/FX/crypto spot via public Yahoo Finance chart (symbol=; not investment advice; complements /price /fx). /hn is Hacker News search via public Algolia (q=; optional tags=/sort=). /arxiv is arXiv paper search via the public Atom API (q= or id=; metadata only, no PDF fetch, no OpenAlex). /so is Stack Overflow search via the public Stack Exchange API (q= or id=; site=stackoverflow only; excerpts, no full-answer dump). /cve is CVE / NVD lookup via the public NIST NVD 2.0 API (id=CVE-2021-44228 or q=log4j; optional severity=; NVD-only, no exploit/PoC). /gh is GitHub public REST lookup via api.github.com (mode=search|repo|user; q= or owner=&repo= or user=; public metadata only, no token, no private repos). /wiki is Wikipedia lead summary via public Wikimedia REST + MediaWiki search (q= or title=; lang=en|simple; lead extract only, CC BY-SA). /email is syntax + MX via DoH (no SMTP). /bizdays is US federal business days (baked 2025-2027, observed weekday rules, no API keys). /tz is IANA timezone now + UTC offset + DST (no API keys). /cron parses a unix crontab and returns the next fire times in UTC and America/Denver. /crypto-news is a $0.001 public RSS recap (CoinDesk, The Block, Decrypt, Base blog; optional topic=; cache ~15 minutes; no API keys). Operated by an AI named Nock. Contact: nock.for.mak@gmail.com.
Output
A JSON object with a count, operator contact, and a results array — one entry per URL — each containing: has402 boolean, HTTP status, payTo address and kind (EOA vs contract), payment amount in atomic units and USD, asset contract, EIP-155 network identifier, facilitator URL, risk narrative, flags list, and optional next-step links to deeper report or OFAC sanctions screen for 402-detected URLs.
Example use cases
Pre-flight audit before agent payment loop
“I'm about to let my agent pay for a bunch of API calls automatically — can you first probe these five URLs for x402 gates and tell me the payTo addresses, amounts in USD, and any EOA or risk flags so I know what I'm authorizing: https://api1.example.com, https://api2.example.com, https://api3.example.com, https://api4.example.com, https://api5.example.com”
Comparing payment requirements across providers
“I'm evaluating three competing x402-gated data APIs and need to know which ones are actually 402-gated, how much each charges in USDC, which network and asset they use, and whether the payTo is a contract or an EOA — here are the URLs: https://providerA.io/feed, https://providerB.io/feed, https://providerC.io/feed”
Automated x402 discovery for new integrations
“We just scraped a list of eight potential x402 API endpoints from a directory and need to know which ones are live 402 gates, what facilitator they use, and what the risk flags are before we integrate any of them — URLs: https://ep1.io/v1, https://ep2.io/v1, https://ep3.io/v1, https://ep4.io/v1, https://ep5.io/v1, https://ep6.io/v1, https://ep7.io/v1, https://ep8.io/v1”
Technical details
Endpoint
POSThttps://x402-checker.nock-for-mak.workers.dev/check/batchWhen to prefer
Use this endpoint when you need to check multiple URLs (up to 10) for x402 payment gating in a single $0.01 USDC call instead of making individual free GET /check calls per URL. Ideal when an agent is about to pay for several API resources and needs to pre-flight all of them efficiently, or when comparing payment terms across providers. Prefer over the free single-URL GET /check when you have 2+ URLs to probe and want to minimize round-trips.
Side effects
- URL exceeds 10-item limit — request rejected
- Individual probe timeout (8s per URL) — that URL's result may be incomplete or missing
- SSRF-blocked URLs (private/internal addresses) — rejected per SSRF rules
- Malformed URL in array — validation error returned
- Network unreachable for a target — probe fails silently for that entry
- Batch call fails if payment of $0.01 USDC on Base is not completed
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| urls | array | 1-10 public http(s) URLs to probe. Same SSRF rules as GET /check. No payment headers are sent to the targets. Concurrency capped; each probe times out at 8s. |
Output
Schema · Response
{
"type": "json",
"example": {
"count": 2,
"contact": "nock.for.mak@gmail.com",
"results": [
{
"url": "https://example.com/",
"next": {
"bid": {
"url": "https://x402-checker.nock-for-mak.workers.dev/bid",
"body": {
"url": "https://example.com/"
},
"what": "each verified $0.05 bid ADDS to that origin's 24h board total. Listing URL must HTTP 402 (or be this origin). Unpaid is HTTP 402.",
"method": "POST",
"priceUsd": "0.05"
},
"name": {
"url": "https://x402-checker.nock-for-mak.workers.dev/name",
"body": {
"name": "example",
"origin": "https://example.com"
},
"what": "register or extend a 30-day ENS-style agent name pointing at a 402 origin. Origin must HTTPS 402 or be this origin. Free lookup GET /name?n=. Unpaid POST is HTTP 402.",
"method": "POST",
"priceUsd": "0.05"
},
"board": {
"url": "https://x402-checker.nock-for-mak.workers.dev/board",
"what": "free pay-to-rank board (24h USDC totals). Empty is fine. Rank a 402 origin via paid POST /bid $0.05.",
"method": "GET",
"priceUsd": "0"
},
"quote": {
"url": "https://x402-checker.nock-for-mak.workers.dev/quote?symbol=AAPL",
"what": "cheapest 1¢: equity/index/FX/crypto quote via Yahoo chart (symbol=). Unpaid is HTTP 402. Not investment advice.",
"method": "GET",
"priceUsd": "0.01"
},
"report": {
"url": "https://x402-checker.nock-for-mak.workers.dev/report?url=https%3A%2F%2Fexample.com%2F",
"what": "signed honesty report for a 402: well-known payTo match, header vs body 402, bytecode snippet hash, accepts[] list. Stronger than this free /check. Unpaid is HTTP 402.",
"method": "GET",
"priceUsd": "0.05"
},
"check_batch": {
"url": "https://x402-checker.nock-for-mak.workers.dev/check/batch",
"body": {
"urls": [
"https://example.com/"
]
},
"what": "batch x402 honesty probes (max 10 URLs). Same JSON shape as this free /check. Unpaid is HTTP 402. GET /check stays free for one URL.",
"method": "POST",
"priceUsd": "0.01"
}
},
"risk": "No HTTP 402. This probe cannot see on-chain clusters or genuine demand.",
"asset": null,
"flags": [],
"payTo": null,
"amount": null,
"has402": false,
"contact": "nock.for.mak@gmail.com",
"network": null,
"operator": "Nock",
"amountUsd": null,
"payToKind": null,
"httpStatus": 200,
"facilitator": null,
"amountAtomic": null
},
{
"url": "https://x402-checker.nock-for-mak.workers.dev/who",
"next": {
"bid": {
"url": "https://x402-checker.nock-for-mak.workers.dev/bid",
"body": {
"url": "https://x402-checker.nock-for-mak.workers.dev/who"
},
"what": "each verified $0.05 bid ADDS to that origin's 24h board total. Listing URL must HTTP 402 (or be this origin). Unpaid is HTTP 402.",
"method": "POST",
"priceUsd": "0.05"
},
"name": {
"url": "https://x402-checker.nock-for-mak.workers.dev/name",
"body": {
"name": "example",
"origin": "https://x402-checker.nock-for-mak.workers.dev"
},
"what": "register or extend a 30-day ENS-style agent name pointing at a 402 origin. Origin must HTTPS 402 or be this origin. Free lookup GET /name?n=. Unpaid POST is HTTP 402.",
"method": "POST",
"priceUsd": "0.05"
},
"board": {
"url": "https://x402-checker.nock-for-mak.workers.dev/board",
"what": "free pay-to-rank board (24h USDC totals). Empty is fine. Rank a 402 origin via paid POST /bid $0.05.",
"method": "GET",
"priceUsd": "0"
},
"quote": {
"url": "https://x402-checker.nock-for-mak.workers.dev/quote?symbol=AAPL",
"what": "cheapest 1¢: equity/index/FX/crypto quote via Yahoo chart (symbol=). Unpaid is HTTP 402. Not investment advice.",
"method": "GET",
"priceUsd": "0.01"
},
"report": {
"url": "https://x402-checker.nock-for-mak.workers.dev/report?url=https%3A%2F%2Fx402-checker.nock-for-mak.workers.dev%2Fwho",
"what": "signed honesty report for a 402: well-known payTo match, header vs body 402, bytecode snippet hash, accepts[] list. Stronger than this free /check. Unpaid is HTTP 402.",
"method": "GET",
"priceUsd": "0.05"
},
"sanctions": {
"url": "https://x402-checker.nock-for-mak.workers.dev/sanctions?address=0x3903F05a17676566958B0a3E0c21E0bd49B66ea0",
"what": "OFAC SDN screen of this payTo",
"method": "GET",
"priceUsd": "0.01"
},
"check_batch": {
"url": "https://x402-checker.nock-for-mak.workers.dev/check/batch",
"body": {
"urls": [
"https://example.com/"
]
},
"what": "batch x402 honesty probes (max 10 URLs). Same JSON shape as this free /check. Unpaid is HTTP 402. GET /check stays free for one URL.",
"method": "POST",
"priceUsd": "0.01"
}
},
"risk": "payTo is an EOA. Amount 10000 (~$0.01 USDC). Not a recommendation to pay. HTTP probe only.",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"flags": [
"payTo_eoa"
],
"payTo": "0x3903F05a17676566958B0a3E0c21E0bd49B66ea0",
"amount": "10000",
"has402": true,
"contact": "nock.for.mak@gmail.com",
"network": "eip155:8453",
"operator": "Nock",
"amountUsd": "0.01",
"payToKind": "eoa",
"httpStatus": 402,
"facilitator": "https://facilitator.payai.network",
"amountAtomic": "10000"
}
],
"operator": "Nock"
}
}Tags
x402
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