Question 1

What prediction market data does KacData provide?

Accepted Answer

Tick-by-tick Kalshi order book snapshots and deltas, trades, ticker updates and market lifecycle events, as Parquet files.

Question 2

Can I download free Kalshi data?

Accepted Answer

Yes. New KacData Free Trial accounts include 600 one-time downloads plus 50 downloads per month, for data older than 3 weeks.

Question 3

Does the Order Book L2 dataset include both YES and NO?

Accepted Answer

Yes. Kalshi order books hold bids only: the yes lists are bids for YES and the nolists are bids for NO. A NO bid at price p is equivalent to a YES ask at 1 − p. KacData keeps Kalshi's yes/no view and does not convert it to bid/ask.

Question 4

How often is the data updated?

Accepted Answer

The data is updated once a day.

Question 5

How do I download Kalshi historical data?

Accepted Answer

Create an account, generate an API key, then download Parquet files directly over HTTP from the KacData API. The dashboard and docs include copy-ready curl and Python examples.

Question 6

Which Kalshi markets and dates are covered?

Accepted Answer

All Kalshi markets from 2026-09-08 (the first day starts at 17:00 UTC), updated once a day. See Kalshi historical data details.

Question 7

Can I backtest prediction market strategies with this data?

Accepted Answer

Yes. KacData is designed for research and backtesting workflows, including tick-level order book replay from the start-of-day book in every L2 file.

Question 8

Has the data been processed?

Accepted Answer

Rows are the messages of the Kalshi WebSocket, with local receive timestamps added. Field names are converted to snake_case, prices and sizes are stored as decimals, and each L2 file starts and ends with a synthesized start-of-day and end-of-day order book so a single day can be replayed on its own.

Question 9

Where is the data collected?

Accepted Answer

Kalshi data is collected in AWS us-east-2 (availability zone ID use2-az1), colocated with Kalshi.

#	market_ticker	timestamp	local_timestamp	event_type	delta_price	delta_size	delta_side	yes_prices	yes_sizes	no_prices	no_sizes
1	KXBTC15M-26OCT150930-30	null	1792070101063667	orderbook_snapshot	null	null	null	[0.5300, 0.5200, ... 0.0010]	[0.0200, 7.1000, ... 4187501.0000]	[0.4600, 0.4500, ... 0.0010]	[2022.3400, 1079.9100, ... 4011468.0000]
2	KXBTC15M-26OCT150930-30	1792070101023000	1792070101063686	orderbook_delta	0.4500	-5.0000	no	null	null	null	null
3	KXBTC15M-26OCT150930-30	1792070101023000	1792070101063687	orderbook_delta	0.4200	5.0000	no	null	null	null	null
4	KXBTC15M-26OCT150930-30	1792070101023000	1792070101063689	orderbook_delta	0.4600	-30.4500	no	null	null	null	null
5	KXBTC15M-26OCT150930-30	1792070101029000	1792070101063735	orderbook_delta	0.4800	1.0000	yes	null	null	null	null
6	KXBTC15M-26OCT150930-30	1792070101029000	1792070101063736	orderbook_delta	0.4100	1.0000	no	null	null	null	null
7	KXBTC15M-26OCT150930-30	1792070101034000	1792070101063788	orderbook_delta	0.4300	-1.0000	no	null	null	null	null
8	KXBTC15M-26OCT150930-30	1792070101038000	1792070101063852	orderbook_delta	0.5100	-39.0000	yes	null	null	null	null

Download Kalshi Historical Data

What you can download

API Example

Frequently asked questions