# Carbon Cashmere Rolling Pearson Correlation

> Carbon Cashmere Rolling Pearson Correlation is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).

Computes rolling Pearson correlation between two cryptocurrencies over a configurable 7–90 day window, returning correlation value, regime classification, trend direction, summary statistics, and a 30-point rolling snapshot.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/rolling-correlation/:pair
- Price: $0.1/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-b99fbf5f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_x-NiOVz7L1MT5xXJa-x_3

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-b99fbf5f
```

Example prompt: What's the rolling 30-day Pearson correlation between BTC and ETH right now — is it strengthening or weakening, and which regime is it in?

## When to prefer this

Use this endpoint when you need quantitative, statistically grounded correlation analysis between two specific crypto assets with regime classification and trend direction — particularly for portfolio diversification research, pair trading analysis, or understanding co-movement dynamics over configurable time windows. Prefer over generic price endpoints when the goal is correlation intelligence rather than raw price data.

## Known failure modes

- Invalid pair format (not BASE-QUOTE) returns 400 error
- Unsupported coin ticker returns 404 or empty data
- Window outside 7–90 day range may return validation error
- Insufficient historical data for very new coins
- Upstream data unavailability causes 503 or stale data

## How this service works

Rolling Pearson correlation between two coins over configurable window (7-90d). Pair format in path: BASE-QUOTE (e.g. /v1/rolling-correlation/BTC-ETH). Returns current correlation, regime classification (strongly_positive/positive/weak/negative/strongly_negative), trend direction (strengthening/weakening/stable), summary statistics over lookback, and rolling snapshot sampled to 30 points. Informational research data — not investment advice.

## Output

Returns the current Pearson correlation coefficient between the two coins, a regime label (strongly_positive, positive, weak, negative, or strongly_negative), a trend direction (strengthening, weakening, or stable), summary statistics over the lookback window, and a 30-point rolling snapshot of the correlation over time.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-carbon-cashmere-de-b99fbf5f/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)