# x402 Checker – POST /bid (Paid Ranking Bid)

> x402 Checker – POST /bid (Paid Ranking Bid) is a paid API for AI agents from x402-checker.nock-for-mak.workers.dev, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Submit a $0.05 USDC bid to boost a URL's ranking on the x402 Checker leaderboard for 24 hours

## Facts

- Endpoint: POST https://x402-checker.nock-for-mak.workers.dev/bid
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-checker-post-bid-paid-ranking-bid-ad3492ca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1-fFOM4nJzofUO7RQANi2

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-checker-post-bid-paid-ranking-bid-ad3492ca -d '<json body>'
```

Example prompt: Submit a $0.05 USDC bid to rank my API at https://myapi.example.com/pay on the x402 Checker leaderboard — call it 'MyPay API' with the topic 'payments' and description 'Fast micropayment endpoint for AI agents'.

## When to prefer this

Use this endpoint when you want to pay to increase the visibility and ranking of an x402-compatible HTTP 402 endpoint on the x402 Checker leaderboard. This is the right endpoint if you want to spend $0.05 USDC to boost a listing for a 24-hour period, optionally supplying metadata like name, slot, topic, and description. It is not for free checks of URLs (use GET /check), reporting issues (use POST /report), or batch URL validation (use POST /check/batch).

## Known failure modes

- Payment not completed or insufficient USDC — bid not credited
- URL field missing or malformed — 400 validation error
- URL does not return HTTP 402 or is not a valid x402 listing — rejection
- Name, slot, topic, or description fields exceed character limits — 400 error
- x402 payment protocol handshake fails — payment not processed, bid not submitted
- Service unavailable on Cloudflare Workers — 503 error

## 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

Returns a JSON object confirming the bid was accepted, including the SKU ('bid'), the submitted URL, the bid amount in USD ($0.05) and atomic units (50000), whether the bid was credited, the operator name, and the operator's contact email.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "description": "http(s) listing URL that returns HTTP 402, or this origin."
  },
  "name": {
   "type": "string",
   "description": "Optional short name. Max 80 chars."
  },
  "slot": {
   "type": "string",
   "description": "Optional slot. Max 40 chars."
  },
  "topic": {
   "type": "string",
   "description": "Optional topic. Max 40 chars."
  },
  "description": {
   "type": "string",
   "description": "Optional one-line description. Max 200 chars."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "sku": "bid",
  "url": "https://x402-checker.nock-for-mak.workers.dev/who",
  "bidUsd": "0.05",
  "contact": "nock.for.mak@gmail.com",
  "credited": true,
  "operator": "Nock",
  "bidAtomic": "50000"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-checker-post-bid-paid-ranking-bid-ad3492ca/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-checker.nock-for-mak.workers.dev](https://www.zero.xyz/host/x402-checker.nock-for-mak.workers.dev/llms.txt)