# x402 Bazaar Rank – Crossref Discovery

> x402 Bazaar Rank – Crossref Discovery is a paid API for AI agents from x402-bazaar-rank.x402-bazaar-rank-worker.workers.dev, paid per call via x402, $0.032/call, status unknown (last checked 2026-10-23).

Returns a ranked list of x402 services tagged 'crossref', scored by real 30-day call volume and unique paying-wallet counts, with a verifiable snapshot receipt.

## Facts

- Endpoint: GET https://x402-bazaar-rank.x402-bazaar-rank-worker.workers.dev/in-crossref?utm_source=zero.xyz
- Price: $0.032/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-bazaar-rank-crossref-discovery-e7123acb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zIfs4Yzy9SMD74Oed_QHH

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-bazaar-rank-crossref-discovery-e7123acb
```

Example prompt: Show me the top crossref services on the x402 bazaar ranked by paying wallets over the last 30 days, with their call counts and prices.

## When to prefer this

Use this endpoint when you need ranked, real-usage-backed discovery of crossref services specifically within the x402 protocol ecosystem. Prefer it over generic API directories when you need verifiable 30-day activity metrics (calls and paying wallets) rather than self-reported or static listings, and when you need a cryptographically receipted snapshot hash for auditability.

## Known failure modes

- No crossref-tagged services indexed returns empty services array with matched:0
- Snapshot stale if index hasn't refreshed — check generatedAt timestamp
- Worker cold start may add latency on first call
- Payment of $0.004 USDC required per call — missing or invalid payment returns 402
- Invalid query parameters may return empty or malformed results

## How this service works

An open index of the machine-to-machine (agent) economy. x402 routes: ranked discovery over the live x402 service market, every indexed service scored by real 30-day calls and paying-wallet bounds, with a receipt naming the snapshot hash and scoring revision. /economy routes, for Tempo MPP, Virtuals ACP, Olas, Masumi, ERC-8004 agent registries, Solana agent registries, Base agent contracts and MCP servers (Official MCP Registry): each protocol's published figures (agent or server counts, transactions or payment events; payers and USD volume only where the source publishes them: payers for x402 and Tempo MPP, USD volume for x402 and Virtuals ACP), each with its unit, window and source; units differ, so totals are not summed. L402 and per-service MPP listings are not covered.

## Output

A JSON object containing a ranked array of crossref-tagged x402 services, each with name, network chain ID, 30-day call count, price in USD, resource URL, and unique payer count over 30 days. Also includes the query metadata (route, operator, limit), total matched count, who declared the data, and a generatedAt timestamp plus snapshot hash for auditability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 25,
  "query": {
   "by": "payers",
   "op": "top",
   "limit": 25,
   "where": {
    "tag": "crossref"
   }
  },
  "route": "/in-crossref",
  "matched": 359,
  "services": [
   {
    "name": "forecast api",
    "network": "eip155:8453",
    "calls30d": 310,
    "priceUsd": 0.01,
    "resource": "https://api.example.com/forecast",
    "payers30d": 42
   }
  ],
  "declaredBy": "agent",
  "generatedAt": "2026-09-17T12:00:00.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-bazaar-rank-crossref-discovery-e7123acb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-bazaar-rank.x402-bazaar-rank-worker.workers.dev](https://www.zero.xyz/host/x402-bazaar-rank.x402-bazaar-rank-worker.workers.dev/llms.txt)