Interactive Guide
Shown: an illustrative order book over time, bids below the mid and asks above it.
Imagine a room where buyers line up on the left and sellers on the right. The person at the front of each line sets the best bid and best ask. The gap between them is the spread. When a buyer gets impatient and crosses over to the seller's side at their price, a trade happens.
Mid price
A market order hits
Try placing a market buy with a large size. Watch how the order eats through the ask side, consuming liquidity level by level. The spread widens. The midprice shifts. This is in its most elemental form.
The book above is simulated. Our measures the depth of real books, and there's a free sample to try.
Derivatives
Open interest values with percentage change, volatility, and OI/price change ratio.
Shown: open_interest, hourly, 1–31 January 2024, from this page's Sample CSV · extreme: 83154.746, 12 Jan, 19:00 UTC · built with open_interest
open_interestOpen Interest tracks the total outstanding derivatives exposure and serves as the balance-sheet backdrop for price action.
Rising open interest means new positions are being opened or expanded, while falling open interest suggests risk is being reduced or closed out.
open_interest_pct_changeOpen Interest % Change shows how quickly positioning expanded or contracted over the interval.
This is often more informative than the raw level because it makes sudden positioning events immediately visible.
open_interest_volatilityOpen Interest Volatility measures how unstable outstanding positioning was inside the bar.
High values can indicate frequent leverage adjustments, position recycling, or stress-driven churn rather than steady accumulation.
oi_price_change_ratioOI/Price Change Ratio compares how much positioning changed relative to the magnitude of the price move.
It helps answer whether price action was accompanied by substantial leverage participation or happened mostly without new positioning.
Open interest (OI) — the total number of outstanding derivative contracts — measures how much leverage the system is carrying. But raw OI is static information. Changes in OI, and their relationship to price, reveal the market's structural state in ways that price alone cannot.
/api/v1/data/open_interest| Field | Name | Description |
|---|---|---|
open_interest | Open Interest | Last open interest value in the interval |
open_interest_pct_change | Open Interest % Change | Percentage change in open interest from the first value to the last value in the interval |
open_interest_volatility | Open Interest Volatility | Standard deviation of tick-to-tick open-interest percentage changes in the interval |
oi_price_change_ratio | OI/Price Change Ratio | Open-interest return divided by mark-price return over the interval |
# Install the Aperiodic CLI into ~/.local/bin
mkdir -p "$HOME/.local/bin"
curl -fsSL https://raw.githubusercontent.com/aperiodic-io/cli/main/install.sh | INSTALL_DIR="$HOME/.local/bin" bash
export PATH="$HOME/.local/bin:$PATH"
# Free preview — no API key required
aperiodic open_interest --preview \
--exchange binance-futures \
--symbol perpetual-BTC-USDT:USDT \
--interval 5m \
--timestamp exchange \
--start-date 2025-05-01 \
--end-date 2025-05-31 \
--output-dir ./data && echo "Saved to $PWD/data"Every new row as it is computed, over WebSocket at wss://stream.aperiodic.io/v1/stream. Authenticate with your API key in the X-API-KEY header and subscribe to channels named open_interest.<exchange>.<interval>, on intervals 1m, 5m, 15m, 30m, 1h, 4h, 1d. Streaming is included on Live plans.
pip install "aperiodic[stream]"import os
from aperiodic import stream
for message in stream(
api_key=os.environ["APERIODIC_API_KEY"],
dataset="open_interest",
exchange="binance-futures",
interval="1m",
symbols=["perpetual-BTC-USDT:USDT"], # omit for every symbol on your plan
):
print(message.channel, message.snapshot, message.data)timestampreqstringTimestamp source. 'exchange' uses the exchange-reported timestamp, 'true' uses actual arrival time at our servers.
exchangetrueintervalreqstringAggregation time interval for the data.
1m5m15m30m1h4h1dexchangereqstringSource exchange for the data.
binance-futuresokx-perpshyperliquid-perpssymbolreqstringTrading pair symbol in the format of Atlas' universal symbology: https://github.com/aperiodic-io/atlas
start_datereqstring<date>Start date for the data range (YYYY-MM-DD format). A metric series starts on the first day of the raw series it is computed from (see /metadata/raw); raw trades and quotes start binance-futures from 2020-01-01, okx-perps from 2019-09-01, hyperliquid-perps from 2025-01-01. Earlier days return no files. How far back you can go depends on the plan: 5 years on Pro, full history on Prime, Prime + Raw and Institutional. An earlier start_date than the plan reaches returns 403.
end_datereqstring<date>End date for the data range (YYYY-MM-DD format). Must be greater than or equal to start_date.
Successful response with download URLs for every existing file covering the range from the series' published start — one per month before 2026-08-01, one per day from 2026-08-01 onwards
filesobject[]requiredFiles covering the requested date range, in chronological order. Data before 2026-08-01 is split by month (one file per calendar month, no `day`); data from 2026-08-01 onwards is split by day (one file per calendar day, with `day` set). The changeover falls on a month boundary, so a given month is served entirely one way or the other; a range spanning it returns the earlier months as monthly files followed by a daily file per day.
yearintegerrequiredYear of the data file
monthintegerrequiredMonth of the data file (1-12)
dayintegerDay of the data file (1-31). Present only on daily files, i.e. those covering 2026-08-01 onwards. Absent on monthly files, which cover an entire calendar month.
urlstring<uri>requiredPresigned URL for direct file download (valid for 5 minutes). URLs are served from dataset-specific subdomains, e.g. ohlcv.aperiodic.io, trade-metrics.aperiodic.io, l1-metrics.aperiodic.io, l2-metrics.aperiodic.io, derivative-metrics.aperiodic.io.
{
"files": [
{
"year": 2026,
"month": 6,
"url": "https://ohlcv.aperiodic.io/binance-futures/1h/BTCUSDT/2026-06.parquet?X-Amz-Expires=300&..."
},
{
"year": 2026,
"month": 7,
"url": "https://ohlcv.aperiodic.io/binance-futures/1h/BTCUSDT/2026-07.parquet?X-Amz-Expires=300&..."
},
{
"year": 2026,
"month": 8,
"day": 1,
"url": "https://ohlcv.aperiodic.io/binance-futures/1h/BTCUSDT/2026-08-01.parquet?X-Amz-Expires=300&..."
},
{
"year": 2026,
"month": 8,
"day": 2,
"url": "https://ohlcv.aperiodic.io/binance-futures/1h/BTCUSDT/2026-08-02.parquet?X-Amz-Expires=300&..."
}
]
}
Prefilled with the shared DEMO-KEY and a free preview slice — send the request to see live data, no account required.
/api/v1/data/preview/open_interest?timestamp=exchange&interval=5m&exchange=binance-futures&symbol=perpetual-BTC-USDT%3AUSDT&start_date=2025-05-01&end_date=2025-05-31