Interactive Guide
An interactive journey through market microstructure: watch orders become prices, feel the spread respond to stress, and discover why these mechanics shape every trade you will ever make.
Every market starts with two opposing lines: buyers and sellers, stacked by price and size. The order book is not just a record — it is the market's living, breathing state.
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.
Try a large size (10+) and watch the spread blow out
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.
Biais, Hillion & Spatt (1995) showed that the shape of the order book — not just the best price — contains predictive information about future price dynamics. The distribution of depth across levels reveals strategic positioning before it shows up as obvious price moves.
The spread is not just a cost — it is a risk price. Market makers set it wide when they're nervous, like a store charging more for something they're not sure they can restock.
Huang & Stoll (1997) decomposed the spread into three components: adverse selection (the risk of trading against someone who knows more), inventory holding (the risk of being stuck with a position), and order processing (the cost of doing business). Drag the slider below and watch all three shift in real time.
Spread Decomposition (Huang & Stoll)
Active Market Makers
7 of 8 still quoting
Notice how market makers withdraw as uncertainty rises. In crisis conditions, only one or two remain — and they demand a massive spread to compensate. A 2 bps average spread that was actually 0.5 bps for 55 seconds and 8 bps for 5 seconds tells a fundamentally different story than a steady 2 bps. The itself predicts future return volatility.
A widening spread is a leading indicator — it signals increased uncertainty about fair value before the price itself visibly reacts. Spread compression signals confident competition among liquidity providers and a regime where execution is cheaper and mean reversion is more reliable.
Need the ticks behind this metric? Prime + Raw includes raw trades.
VWAP and TWAP are both price averages over an interval. But they weight observations differently — by volume and by time, respectively — and the divergence between them is itself a powerful signal about the quality of price moves.
/api/v1/data/vtwap
Market Data
vwapVWAPTrade-size-weighted average price in the intervaltwapTWAPArithmetic average trade price in 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 vtwap --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"timestampreqstringTimestamp source. 'exchange' uses the exchange-reported timestamp, 'true' uses actual arrival time at our servers.
exchangetrueintervalreqstringAggregation time interval for the data. Sub-minute intervals (15s, 30s) require a Tier 3 subscription.
15s30s1m5m15m30m1h4h1dexchangereqstringSource 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). Data is partitioned by year and month.
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 file covering the range — 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/vtwap?timestamp=exchange&interval=5m&exchange=binance-futures&symbol=perpetual-BTC-USDT%3AUSDT&start_date=2025-05-01&end_date=2025-05-31