Free Open Interest API

Endpoint

Examples

curl "https://xoomar.com/api/markets/open-interest/btc?period=1d"

import requests

r = requests.get("https://xoomar.com/api/markets/open-interest/btc", params={"period": "1d"})
for row in r.json()["data"]:
    print(f"{row['ts']}: ${float(row['openInterestValue']):,.0f}")

const res = await fetch("https://xoomar.com/api/markets/open-interest/btc?period=1d");
const { data } = await res.json();
console.log(data.map(r => `${r.ts}: $${Number(r.openInterestValue).toLocaleString()}`));

Limits

• The history is hourly, not tick data.
• History starts in January 2021 for the major symbols; the free API returns the last six months.
• The history is Binance only; live open interest per venue is in the funding rates API.
• The long/short ratios are exchange-reported and null where a venue doesn't publish them.

Main features

• Hourly open interest history from Binance, starting in January 2021; the free API returns the last six months.
• Both contract count and USD notional per row, so you can chart either without a conversion.
• Global long/short account ratio and top-trader position ratio where the exchange publishes them.
• Up to 5,000 rows per call with from and to dates and a 1h or 1d period.
• The same data as the open interest dashboards; what you see on the page is what the API returns.

Example

Request

curl "https://xoomar.com/api/markets/open-interest/btc?period=1d"

Response, live at 2026-10-17 15:48 UTC, trimmed

{
  "data": [
    {
      "ts": "2026-10-17T00:00:00.000Z",
      "openInterest": "94190.573375000000",
      "openInterestValue": "7681552260.74794375",
      "longShortRatio": "1.7107687500000000",
      "exchange": "binance"
    },
    {
      "ts": "2026-10-16T00:00:00.000Z",
      "openInterest": "94719.496833333333",
      "openInterestValue": "7758877480.99983333",
      "longShortRatio": "1.5982666666666667",
      "exchange": "binance"
    }
  ],
  "updatedAt": "2026-10-17T15:48:29.495Z",
  "source": "xoomar.com",
  "docs": "https://xoomar.com/markets/api",
  "license": "https://xoomar.com/terms",
  "attribution": "Credit XOOMAR with a link to the dataset page on xoomar.com when you republish this data",
  "meta": {
    "source": "Binance",
    "sourceAttribution": "Open interest history: Binance.",
    "notice": "10 requests a minute without a key, 30 with a free key. Get a free key at https://xoomar.com/signup?utm_source=api, register your app at https://xoomar.com/developers/register?utm_source=api, and credit the data as \"Data: XOOMAR\" together with the sourceAttribution line."
  }
}

One row per symbol, venue and hour; a later correction replaces the row. openInterest is in contracts, openInterestValue in USD.

What people build with it

Response shape

Every endpoint returns the same JSON envelope: { data, updatedAt, source, docs, license, attribution, meta }. In meta, source names who publishes the data and sourceAttribution is the credit line to show with it. The data field is an array of records with these fields:

Query params: period=1h or 1d (default 1h), from and to as ISO dates. History starts in 2021 for the majors; the free API returns the last six months. Up to 5,000 rows per call.

Numeric fields typed string in the table carry exact decimals; parse them with your language's decimal type. No key needed to start: 10 requests a minute per IP without a key and 30 a minute with a free account key, with at least six months of history. A 429 response carries a Retry-After header in seconds. Credit XOOMAR with a link to the dataset page when you republish the data; the data terms are on the terms page.

A free account key raises the limit; send it in an X-API-Key header.