# Crypto Options Put/Call Ratio & Sentiment API
> The single headline gauge of how the crypto options market is positioned, computed live from Deribit's public option book — no key, nothing stored. The put/call ratio is the amount of put activity divided by call activity: a low ratio means the market is loaded with calls (bullish, greedy positioning), a high ratio means puts dominate (hedging, fear). The ratio endpoint returns, for a currency (BTC or ETH), the market-wide put/call ratio computed two ways — by open interest (the standing positioning) and by 24-hour volume (today's flow) — with the call and put totals, the spot index and a plain-language sentiment label. The expiries endpoint breaks the put/call ratio down by expiry, revealing the term structure of sentiment: whether hedging is concentrated in the near term or further out. This is the aggregate options put/call sentiment cut for crypto — distinct from the US-equity put/call API (a different market), the max-pain / open-interest positioning view, the implied-vol skew surface and the gamma-exposure APIs in the catalogue. Below roughly 0.7 is call-heavy and bullish, above 1.0 put-heavy and defensive; it is most useful read as a contrarian gauge. Currency is BTC or ETH, the two assets Deribit lists liquid options for.

## Authentication
All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys.

```bash
curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/cryptoputcall-api/..."
```

## Pricing
- **Free** (Free) — 500 calls/Mo, 2 req/s
- **Starter** ($11/Mo) — 11,400 calls/Mo, 6 req/s
- **Pro** ($35/Mo) — 68,000 calls/Mo, 16 req/s
- **Business** ($78/Mo) — 360,000 calls/Mo, 40 req/s

## Endpoints

### Put/Call

#### `GET /v1/expiries` — Put/call ratio by expiry (term structure)

**Parameters:**
- `currency` (query, required, string) — BTC or ETH Example: `BTC`

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/cryptoputcall-api/v1/expiries?currency=BTC"
```

#### `GET /v1/ratio` — Market-wide put/call ratio & sentiment

**Parameters:**
- `currency` (query, required, string) — BTC or ETH Example: `BTC`

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/cryptoputcall-api/v1/ratio?currency=BTC"
```

### Meta

#### `GET /v1/meta` — Spec

**Example:**
```bash
curl -H "x-oanor-key: $KEY" \
  "https://api.oanor.com/cryptoputcall-api/v1/meta"
```


---
Marketplace page: https://www.oanor.com/api/cryptoputcall-api
OpenAPI spec: https://www.oanor.com/api/cryptoputcall-api/openapi.json