# Blockchain.com Explorer Market Cap Chart API

> Blockchain.com Explorer Market Cap Chart API is a paid API for AI agents from api.blockchain.info, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Retrieves historical Bitcoin market capitalization chart data from Blockchain.com Explorer, with configurable timespan, rolling averages, and output format

## Facts

- Endpoint: POST https://api.blockchain.info/explorer-gateway-kt/x402/charts/market-cap?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blockchain-com-explorer-market-cap-chart-api-717a4ee7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6mjQ4hkxKwC17X_s3HwGh

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 blockchain-com-explorer-market-cap-chart-api-717a4ee7 -d '<json body>'
```

Example prompt: Pull Bitcoin's market cap chart data from Blockchain.com for the past year using an 8-hour rolling average, and give me the results in JSON format.

## When to prefer this

Choose this endpoint when you need authoritative historical Bitcoin market capitalization data directly from Blockchain.com's explorer infrastructure, especially when you want configurable rolling averages, flexible timespans (hours to years), and the choice between JSON and CSV output. Prefer this over generic crypto data APIs when Blockchain.com provenance is important or when you need fine-grained control over averaging windows and sampling.

## Known failure modes

- Invalid timespan format returns an error (e.g. unsupported duration string)
- Invalid rollingAverage window string causes a bad request response
- Payment not included or insufficient USDC triggers a 402 Payment Required error
- Unsupported format enum value (not 'json' or 'csv') returns a validation error
- Network or gateway timeout if Blockchain.com upstream is unavailable
- Rate limiting if too many requests are sent in rapid succession

## How this service works

Paid AI-agent access to Blockchain.com Explorer API

## Output

Returns a structured JSON object (or raw CSV) containing historical Bitcoin market capitalization data points with timestamps, optionally including metadata about the chart and values smoothed by a configurable rolling average window. JSON responses include metadata fields and a values array; CSV responses contain timestamp and value columns only.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "cors": {
   "type": "boolean",
   "default": false,
   "description": "Enable CORS headers"
  },
  "format": {
   "enum": [
    "json",
    "csv"
   ],
   "type": "string",
   "default": "json",
   "description": "Response format:\n- `json` — Returns structured JSON with metadata and values\n- `csv` — Returns raw CSV data with timestamp and value columns (no metadata)\n"
  },
  "sampled": {
   "type": "boolean",
   "default": true,
   "description": "Apply sampling to reduce data points"
  },
  "metadata": {
   "type": "boolean",
   "default": false,
   "description": "Include metadata in response"
  },
  "timespan": {
   "type": "string",
   "default": "1y",
   "example": "1y",
   "description": "Time period (e.g., \"24h\", \"7d\", \"1y\", \"3y\")"
  },
  "rollingAverage": {
   "type": "string",
   "default": "8h",
   "example": "8h",
   "description": "Rolling average window (e.g., \"8h\", \"24h\")"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "format": "application/json",
 "example": {
  "name": "Market Capitalization",
  "unit": "USD",
  "period": "day",
  "status": "ok",
  "values": [
   {
    "x": 1704067200,
    "y": 1867423000000
   },
   {
    "x": 1704153600,
    "y": 1900512000000
   }
  ],
  "description": "The total USD value of bitcoin supply in circulation, as calculated by the daily average market price across major exchanges."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blockchain-com-explorer-market-cap-chart-api-717a4ee7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.blockchain.info](https://www.zero.xyz/host/api.blockchain.info/llms.txt)