# x402 Crypto Top Markets by Market Cap

> x402 Crypto Top Markets by Market Cap is a paid API for AI agents from x402-data-api.sigrunner.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-29).

Returns a ranked list of top cryptocurrencies by market cap, including price, market cap, 24h volume, and 24h percent change, with optional limit up to 100.

## Facts

- Endpoint: GET https://x402-data-api.sigrunner.workers.dev/crypto/markets-top?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-crypto-top-markets-by-market-cap-656eb685
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_g2fjuVyj_M_05TLtZ8GQJ

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-crypto-top-markets-by-market-cap-656eb685
```

Example prompt: Give me a market snapshot of the top 25 cryptocurrencies ranked by market cap — I want to see each coin's current price, market cap, 24h volume, and how much it's moved in the last day.

## When to prefer this

Use this endpoint when you need a ranked, multi-coin market snapshot sorted by market cap — ideal for portfolio benchmarking, market overviews, or any scenario requiring a broad view of the leading crypto assets. Prefer this over trending or gainers/losers endpoints when market-cap ranking is the primary sorting criterion rather than momentum or recent price action.

## Known failure modes

- Invalid or out-of-range `limit` value (e.g. above 100) may return an error or be clamped
- CoinGecko upstream downtime or rate limiting may cause failures or stale data
- Payment failure via x402 protocol will block the request ($0.003 USDC required per call)
- Network timeout from Cloudflare Workers if CoinGecko response is slow

## How this service works

Top coins by market cap (CoinGecko): price, market cap, 24h volume, 24h change; ?limit= up to 100. No required params. Use when an agent needs a ranked market snapshot.

## Output

Returns a JSON array of coin objects ranked by market cap, each containing the coin symbol, current price in USD, 24-hour percent price change, and optionally market cap and 24h volume. The number of results is controlled by the optional `limit` parameter (default behavior returns top coins, up to 100).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "limit": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "coins"
     ],
     "properties": {
      "coins": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "symbol",
         "price_usd",
         "change_24h_pct"
        ],
        "properties": {
         "symbol": {
          "type": "string"
         },
         "price_usd": {
          "type": "integer"
         },
         "change_24h_pct": {
          "type": "number"
         }
        }
       }
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "coins": [
   {
    "symbol": "BTC",
    "price_usd": 82028,
    "change_24h_pct": 1.07
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-crypto-top-markets-by-market-cap-656eb685/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-data-api.sigrunner.workers.dev](https://www.zero.xyz/host/x402-data-api.sigrunner.workers.dev/llms.txt)