GET /oi/{coin}

$0.015 USDC

Open interest for one Hyperliquid perpetual and how it has moved. Open interest is counted in contracts of the market’s price_unit (BTC for BTC), not in USD: multiply by price for the USD notional. Changes are fractions (0.0312 = +3.12%), each measured against the stored reading closest to that age.

Request

GET https://api.cerebruspulse.xyz/oi/{coin}

Path Parameters

Parameter	Type	Required	Description
`coin`	string	Yes	Market symbol, case-insensitive (`BTC`, `ETH`, `SOL`). `GET /coins` lists them.

Response

Field	Type	Description
`endpoint`	string	`oi`
`coin`	string	The symbol, upper-case
`market_symbol`	string	Hyperliquid’s name for the market (`kPEPE` for PEPE)
`price_unit`	string	The contract unit: `1 BTC`, or `1000 PEPE` for a 1000-token market
`timestamp_iso`	string	When the response was computed (UTC)
`price`	number \| null	Hyperliquid mid price in USD per `price_unit`
`open_interest.current`	number	Open interest in contracts of `price_unit`, not USD
`open_interest.delta_1h`	number \| null	Change over about 1 hour, as a fraction; null when no stored reading is within ±25% of that age
`open_interest.delta_4h`	number \| null	Change over about 4 hours, as a fraction
`open_interest.delta_24h`	number \| null	Change over about 24 hours, as a fraction
`open_interest.delta_windows_seconds.<window>`	number \| null	How old the reading each delta compares against actually was, for `1h`, `4h` and `24h`
`open_interest.history_age_seconds`	number \| null	Age of the newest stored reading
`open_interest.percentile`	number \| null	Where current OI ranks among the stored readings (up to the last 500), 0–100; null with fewer than 20
`open_interest.percentile_window_hours`	number \| null	The span of history the percentile covers, in hours (about a day today)
`open_interest.trend`	string	From `delta_4h`: `RISING` (> +3%), `FALLING` (< −3%), `FLAT`, or `UNKNOWN`
`open_interest.price_change_4h`	number \| null	Price change over the same window as `delta_4h`, as a fraction
`open_interest.price_oi_divergence`	string	`BEARISH_DIV` (price up > 1% while OI fell > 2%), `BULLISH_DIV` (price down > 1% while OI rose > 2%), `NONE`, or `UNKNOWN`
`meta`	object	Common metadata (Response Schemas)
`meta.offering`	string	`pulse_oi`

meta.as_of holds market_data, oi_history (the newest stored reading) and, when the 4-hour reference price came from a candle, candles_1h. meta.warnings carries stale_oi_history when the newest stored reading is more than an hour old.

Example

GET /oi/BTC: real engine output on market data captured at 2026-09-24 17:05 UTC. Lists are cut to 3 items. Live responses may also carry meta.disclaimer, which the gateway adds.

{
  "endpoint": "oi",
  "coin": "BTC",
  "market_symbol": "BTC",
  "price_unit": "1 BTC",
  "timestamp_iso": "2026-09-24T17:05:00Z",
  "open_interest": {
    "current": 39370.3015,
    "delta_1h": 0.0154,
    "delta_4h": 0.0312,
    "delta_24h": 0.0063,
    "delta_windows_seconds": {
      "1h": 3901,
      "4h": 14701,
      "24h": 86701
    },
    "history_age_seconds": 1200.8,
    "percentile": 88.5,
    "percentile_window_hours": 25.8,
    "trend": "RISING",
    "price_change_4h": 0.0138,
    "price_oi_divergence": "NONE"
  },
  "price": 84512.5,
  "meta": {
    "provider": "Cerebrus Pulse",
    "offering": "pulse_oi",
    "execution_ms": 0,
    "data_age_seconds": 60,
    "as_of": {
      "market_data": "2026-09-24T17:04:00Z",
      "oi_history": "2026-09-24T16:45:00Z",
      "candles_1h": "2026-09-24T13:00:00Z"
    },
    "sources": [
      {
        "name": "Hyperliquid",
        "url": "https://hyperliquid.xyz"
      }
    ]
  }
}

Errors

Status	Reason
400	No open interest for the market (not charged)
402	Payment required (the standard x402 flow)
404	Unknown coin (before any price is quoted)
429	Rate limit exceeded
503	Service disabled, payments down, or an upstream feed is missing or stale; no price is quoted
504	Engine timeout (not charged)