How to get funding rates and open interest

The short way

Ask the venue. On the largest perpetual books both numbers are public, and neither endpoint wants a key, an account or a funded balance.

GET https://fapi.binance.com/fapi/v1/fundingRate?symbol=BTCUSDT&limit=100
GET https://fapi.binance.com/futures/data/openInterestHist?symbol=BTCUSDT&period=5m
GET https://api.bybit.com/v5/market/funding/history?category=linear&symbol=BTCUSDT
GET https://api.bybit.com/v5/market/open-interest?category=linear&symbol=BTCUSDT&intervalTime=5min

Binance's market data API returns settled funding rates with the millisecond timestamp each one settled at, and an open-interest series at periods from five minutes upward. Bybit's is the same shape under different parameter names. Both meter you per IP rather than per key, so containers behind one egress address share one budget, and Bybit returns 403 to any request from a US or mainland China address — which decides the question before any feature does.

If you want more than one venue, do not write that loop first. Coinalyze gives you sixteen venues of funding, predicted funding, open interest and liquidations through a free key at 40 calls a minute. That is the whole short way for most people. The rest of this page is about why the numbers that come back cannot simply be put in the same column.

What the options are

One venue, direct. Binance, Bybit and OKX each publish the funding rate for the coming settlement, the settled funding history and open interest without authentication. Use them when the question is about one book — this venue's positioning, this venue's payments — and accept three costs: rate limits counted per IP, terms you have to read before showing anyone the result, and a normalisation job that is now yours rather than a vendor's.

Every venue at once, free. Coinalyze is a futures screener with an API attached, and the API is on the free tier along with everything else. Twelve endpoints cover supported exchanges, markets, current and historical open interest, current, predicted and historical funding, liquidations, the long/short ratio and OHLCV. The catch is memory: the documentation states that 1,500 to 2,000 datapoints are kept for any intraday granularity from one minute to twelve hours and the old ones are deleted each day, so at one-minute resolution that is somewhere between 25 and 33 hours of history, permanently. Daily bars are kept.

Every venue at once, paid. The CoinGlass API is the widest list in this catalogue — thirty futures venues, including dYdX, Hyperliquid, Drift, Paradex and Lighter alongside the usual names. Funding and open interest arrive as OHLC candles per pair and aggregated across exchanges, with stablecoin-margined and coin-margined kept apart rather than summed, and those candle endpoints are on every plan. What the plan ladder buys is resolution and licence: the 35-dollar tier offers nothing finer than a four-hour bar, minute bars start at the 379-dollar tier, and the two cheapest plans are marked personal use.

Already rescaled. Velo is a derivatives terminal with the dataset behind it sold in the same subscription, and its funding rates are normalised to a per-eight-hour figure across venues — the one conversion most products leave to the reader. Open interest is broken down by the venue it came from rather than merged, which is the difference between "open interest rose" and "open interest rose on Bybit while Binance was flat". Read the billing terms first: on monthly billing the archive is three months deep, and the full five-plus years needs the annual plan.

Where this breaks

The settlement interval is a property of the symbol, not of the market. OKX's own explainer says the fee is charged or paid every 8 hours, at 00:00, 08:00 and 16:00 UTC, "by default, unless specified otherwise (i.e. every 1, 2 or 4 hours)". Bybit publishes fundingInterval per instrument and documents its unit as minutes, and its funding-history page warns outright that each symbol has a different funding interval. Binance keeps a separate endpoint whose entire job is to list the symbols whose fundingIntervalHours has been adjusted away from the default. Hyperliquid pays every hour: its documentation states that the formula produces an eight-hour rate and that one eighth of it is paid hourly, capped at 4% an hour. Two venues quoting "0.01%" are quoting the same string and two different quantities, and neither the funding rate itself nor any chart of it tells you which.

So nothing is comparable until you rescale it, and the rescaling needs a number you have to fetch separately:

# The venue quotes a rate per settlement. Convert before putting two venues side by side.
rate = 0.0001            # one settlement's rate, exactly as the endpoint returned it
interval_hours = 8       # Binance fundingIntervalHours; Bybit fundingInterval / 60; 1 on Hyperliquid

per_8h = rate * (8 / interval_hours)
annualised = rate * (24 / interval_hours) * 365

That annualised figure is a convention, not a fact: it assumes the rate persists and it ignores compounding. Write down which convention you used, because the same series published two ways is how a chart ends up disagreeing with itself.

Predicted funding and realised funding are two different series. The rate a ticker shows belongs to a settlement that has not happened and keeps being recalculated until it does — OKX states that the fee is assessed using the funding rate calculated in the minute before assessment. The settled number is the one the funding-history endpoint returns, stamped with the time it settled. Coinalyze ships current, predicted and historical funding as three separate endpoints, which is the same distinction admitted in a product surface. Storing a predicted rate in the row where a realised one belongs is a silent error: it never throws, it just leaves you with a history nobody else can reproduce.

Open interest is quoted in three different units, and only some of the pages say which. Bybit documents the unit of its open-interest figure per contract type in one line: BTCUSD, the inverse contract, is in USD, and BTCUSDT, the linear one, is in BTC. Binance's COIN-M open-interest statistics annotate sumOpenInterest as unit: cont and sumOpenInterestValue as unit: base asset — so the second field is a quantity of coin, not a dollar figure — while the USDⓈ-M page carries the same two field names with no unit annotation at all. And a count of contracts only becomes a quantity through the contract size, which is published per instrument in exchange information and is not the same number on every symbol. Three denominations, one metric name; see open interest for what the metric itself does and does not count.

A cross-venue total is a sum of numbers defined differently. Every aggregate figure is the result of a conversion per instrument, a choice of denominator, and a decision about which venues are in the population — Coinalyze's sixteen, CoinGlass's thirty and Velo's six are three different markets before anyone converts anything. Two smaller traps sit inside that. Coinalyze lists tokenized equity and commodity derivatives in the same table, marked "(Derivatives)", so a total read off the top of it is not a crypto total. And its aggregated per-coin charts are not real-time by the vendor's own notice, while the markets table is. The same problem one layer down is where the bitcoin price actually comes from.

The history is shorter than the chart implies. Binance's open-interest statistics endpoint says plainly that only the data of the latest 1 month is available; the free funding-rate history is deeper, and deeper still in the flat-file archive on the vendor's public file host. Bybit's open interest reaches back to the symbol's launch and no further, which for a perpetual listed last quarter is last quarter. Coinalyze's rolling window is the 25 to 33 hours described above. On CoinGlass the ladder is the history: four-hour bars and coarser on the cheapest plan, and twelve days is the deepest minute history sold off the shelf. Nothing here is a research archive, and paying more mostly buys resolution rather than years.

Pulling it and publishing it are separate questions. The endpoints are open; the terms behind them are not, and they reach the numbers rather than just the software — what exchange API terms actually let you do is the long version. CoinGlass reserves commercial use for its third tier, and Velo's terms name derived data explicitly, which covers a chart you publish from it.

If you outgrow this

If the problem is that you are polling, buy a key rather than a bigger loop. CoinGlass sells the cross-venue version of what you were assembling by hand, with a documented request ceiling and two response headers that report your usage, and Velo has a usage-based tier at two cents a call that does not appear on its pricing page unless the URL asks for it.

If the problem is that the numbers must line up, either take a product that has already done the conversion — Velo's per-eight-hour normalisation is the clearest example in this catalogue — or own it yourself, in writing: interval per symbol, unit per contract, venue list, and the date each was last checked. The second is more work and it is the only version that survives somebody asking how the figure was built.

If the problem is depth, that is an archive purchase rather than an API upgrade. Amberdata publishes a start date per dataset per venue, which is the useful form: funding rates on 16 of its 20 futures venues with the earliest at May 2016 on BitMEX, open interest on 21 rows, liquidations on only 10. Coin Metrics carries funding, predicted funding, open interest, liquidations and greeks across a 68-venue reference set, with a Parquet-and-Snowflake delivery path beside the API.

If the problem is options rather than perpetuals, none of the above is the answer. Laevitas is the card with a calibrated volatility surface and greeks behind it, and its key starts at 500 dollars a month.

And if what you actually want is a screen rather than a feed, the free web terminal at CoinGlass and the positioning metrics at Hyblock Capital are the browser versions of this page's subject — Hyblock gates its API to the Professional plan, at three months of history, or three years on the annual plan. If candles are what you are really after, how to pull OHLCV from an exchange is the neighbouring task.