# Carbon Cashmere Hurst Exponent API

> Carbon Cashmere Hurst Exponent API is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.12/call, status unknown (last checked 2026-09-15).

Computes the Hurst exponent via rescaled range (R/S) analysis across 3 timescales (7d/30d/full) for a given cryptocurrency, enabling regime detection between mean-reverting, random-walk, and trending market states.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/hurst/:coin
- Price: $0.12/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-carbon-cashmere-de-7dbcf8cc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_f3AyfFuiPJYnHYJ_uEMUZ

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 api-carbon-cashmere-de-7dbcf8cc
```

Example prompt: What's the Hurst exponent for ETH right now — is it trending, mean-reverting, or a random walk across the 7-day, 30-day, and full-period timescales?

## When to prefer this

Use this endpoint when you need quantitative regime detection for a specific cryptocurrency to decide between trend-following and mean-reversion trading strategies. It is ideal for AI agents performing strategy allocation, regime-aware backtesting, or systematic research on crypto market dynamics. Prefer this over general price endpoints when you specifically need a statistical characterization of market persistence across multiple timescales.

## Known failure modes

- Unsupported coin ticker returns an error — only 34 specific coins are supported (e.g. BTC, ETH, SOL)
- Coin ticker provided in lowercase may fail — must be uppercase
- Insufficient historical price data for a given timescale may result in incomplete or null Hurst values
- Payment failure or missing x402 payment header returns 402 Payment Required
- Network timeout or upstream data source unavailability returns 5xx error

## How this service works

Hurst exponent via rescaled range (R/S) computed across 3 timescales (7d/30d/full). H<0.45 = mean-reverting, H~0.5 = random walk, H>0.55 = trending. Used for regime detection and strategy allocation. Informational research data — not investment advice.

## Output

Returns the Hurst exponent value computed via rescaled range (R/S) analysis for the requested coin across three timescales (7d, 30d, and full history), along with a regime classification: H<0.45 indicates mean-reverting behavior, H~0.5 indicates a random walk, and H>0.55 indicates a trending market. Also includes the coin symbol and metadata.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-carbon-cashmere-de-7dbcf8cc/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)