# Carbon & Cashmere BTC Funding Rate History API

> Carbon & Cashmere BTC Funding Rate History API is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.02/call, status down (last checked 2026-09-14).

Returns historical Bitcoin perpetual futures funding rate time series with statistical summaries (avg, max, min, current) over a configurable lookback window.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/history/funding/BTC
- Price: $0.02/call
- Payment: x402
- Status: down
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/carbon-cashmere-btc-funding-rate-history-api-2a4d5988
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__HYpBrf5PL-hglk5r7dHh

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-btc-funding-rate-history-api-2a4d5988
```

Example prompt: Pull the last 30 days of Bitcoin perpetual futures funding rate history from Carbon & Cashmere — I want to see the average, max, min, and current rate along with the full 8-hour interval series.

## When to prefer this

Use this endpoint when you need structured historical Bitcoin funding rate data with pre-computed statistics (avg/max/min/current) and annualized percentages — especially for trend analysis, mean-reversion research, or sentiment inference from funding rate dynamics. Prefer this over raw exchange APIs when you want ready-to-use aggregated stats without additional computation.

## Known failure modes

- Invalid or unsupported symbol returns an error response
- Network timeout if the upstream data source is unavailable
- Payment failure via x402 protocol blocks the request
- Malformed query parameters may return a 400 bad request
- Historical data may have gaps during exchange outages

## How this service works

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

## Output

A JSON object containing: the symbol (BTCUSDT), lookback window in days, interval (8h), aggregate stats (sample count, average rate, max rate, min rate, current rate), and a chronological series array of timestamps with raw rate and annualized percentage for each interval.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "days": 30,
  "stats": {
   "samples": 90,
   "avg_rate": 0.00008,
   "max_rate": 0.0003,
   "min_rate": -0.0002,
   "current_rate": 0.0001
  },
  "series": [
   {
    "ts": "2026-04-01T00:00:00Z",
    "rate": 0.0001,
    "annualized_pct": 10.95
   }
  ],
  "symbol": "BTCUSDT",
  "interval": "8h"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/carbon-cashmere-btc-funding-rate-history-api-2a4d5988/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)