Futures — Basis

GET /futures/basis/:symbol

Spot vs perpetual futures price basis (carry-trade spread analysis).

Cost: $0.02 USDC

Path Parameters

Param	Type	Description
symbol	string	Symbol (e.g. BTC, ETH, SOL)

Request Example

curl -H "x-payment: <proof>" \
  https://api.foursec.xyz/futures/basis/BTC

Response

{
  "symbol": "BTC",
  "timestamp": "2026-07-08T14:30:00Z",
  "spot_price": 57795.10,
  "exchanges": {
    "binance": {
      "perp_price": 57800.32,
      "basis_usd": 5.22,
      "basis_pct": 0.009,
      "basis_annualized_pct": 3.29,
      "direction": "contango"
    },
    "okx": {
      "perp_price": 57802.10,
      "basis_usd": 7.00,
      "basis_pct": 0.012,
      "basis_annualized_pct": 4.38,
      "direction": "contango"
    },
    "bybit": {
      "perp_price": 57798.50,
      "basis_usd": 3.40,
      "basis_pct": 0.006,
      "basis_annualized_pct": 2.19,
      "direction": "contango"
    }
  },
  "best_carry_trade": {
    "exchange": "okx",
    "annualized_yield_pct": 4.38,
    "strategy": "long_spot_short_okx_perp"
  }
}

Basis Direction

Direction	Meaning
contango	Perp price > spot price (common in bullish markets)
backwardation	Perp price < spot price (bearish or unusual demand for shorts)

Carry Trade Strategy

When basis is in contango, you can earn the spread by:

1. Buying spot (hedge against price risk)
2. Shorting the perpetual on the exchange with highest basis
3. Collecting the basis as the spread converges

Data Source

Spot price from Binance REST API. Perp prices from CCXT (Binance, OKX, Bybit). Cache TTL: 30 seconds.