# Carbon & Cashmere Volatility API – BTC

> Carbon & Cashmere Volatility API – BTC is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns multi-model Bitcoin volatility metrics including realized volatility across time windows, range-based estimators (Parkinson, Garman-Klass), downside volatility, and volatility-of-volatility.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/volatility/BTC
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/carbon-cashmere-volatility-api-btc-18808daa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wpnrSqQ-75yrB_Ih_l6c_

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 carbon-cashmere-volatility-api-btc-18808daa
```

Example prompt: What are the current volatility metrics for Bitcoin — including the 7-day and 30-day realized vol, the Parkinson and Garman-Klass range-based estimates, and the downside volatility?

## When to prefer this

Use this endpoint when you need rigorous, multi-model volatility estimates for Bitcoin specifically — particularly when you need range-based estimators (Parkinson, Garman-Klass) alongside standard realized volatility and downside risk, rather than a single implied or simple rolling volatility figure.

## Known failure modes

- Invalid or unsupported symbol returns an error
- Payment not processed (x402 payment required, insufficient USDC balance)
- Upstream data unavailable leads to stale or missing metrics
- Rate limiting if too many calls in short succession

## How this service works

Professional crypto market intelligence. Real-time prices, signals, and market scoring.

## Output

Returns a JSON object with Bitcoin's realized volatility over 7d, 30d, and full period; Parkinson and Garman-Klass range-based volatility estimates; 30-day downside volatility; and 30-day volatility-of-volatility, along with an informational disclaimer.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "_meta": {
   "disclaimer": "Informational research data only — not investment advice."
  },
  "symbol": "BTC",
  "range_based": {
   "parkinson": 0.41,
   "garman_klass": 0.4
  },
  "downside_30d": 0.28,
  "realized_vol": {
   "7d": 0.32,
   "30d": 0.38,
   "full_period": 0.42
  },
  "vol_of_vol_30d": 0.09
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/carbon-cashmere-volatility-api-btc-18808daa/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.carbon-cashmere.de](https://www.zero.xyz/host/api.carbon-cashmere.de/llms.txt)