A day trading simulator for small caps, on real market days
Hindsight Markets is a day trading simulator built on real past market days. Pick a day and the whole US market plays out again as if it were live, every trade and every quote, from the 4:00 a.m. pre-market to after-hours. You practice day trading the small caps that ran that morning with simulated money, seeing only what traders could see at that moment.
Who it is for
It is built for small-cap momentum day traders: the gappers, the low-float runners, the news movers and the halts. The tools are the ones those traders use every morning, a scanner to find the stock, Level 2 and the tape to read it, hotkeys and every order type to trade it, and a journal to review it. It is not a backtester. You trade by hand, the way you would on a live day, and nothing runs a strategy for you.
What makes practising on a real past day different
Most practice accounts trade today's market, so you only get to practise during market hours, and a slow day teaches very little. A replay of a real day gives you the morning a stock actually ran, as many times as you need it, whenever you have time.
The whole market replays, not one symbol. A replay is a day. Find the mover on your scanner, pull it up, then switch to another name from a scanner row, a watchlist or the search box. One account and one P&L follow you across everything you touch.
Level 2 and the tape, as they traded. The full order book, exchange by exchange, with your own orders marked at their price, and every print on time and sales.
Scanners that only know that moment. In a replay the scan reruns across the whole market every minute, using only what was known by then. Top gainers, gappers, volume, relative volume and a low-float small-cap scan come ready, and you can build your own.
News and SEC filings, point in time. Headlines and filings arrive at the moment they were published. Float, short interest and earnings are what was known that day.
Halts and LULD under that day's rules. Limit up-limit down bands are enforced as they applied on that date, so no fill goes through a band. In a halt, market orders do not fill and your limit waits for the reopen.
A journal that writes itself. Every trade is recorded with its executions, its slippage and how far it went for you and against you. Open one and you are back at that moment, thirty seconds before you were in, to watch it or take it again.
How a practice session runs
- Pick a trading day and where to start it: the 4:00 a.m. pre-market, the 9:30 bell, or any time you choose.
- Open a low-float gainers scan and wait for a stock to show up on it, the way you would on a live morning.
- Trade it with your hotkeys or the order ticket. Slow the replay to half speed while you learn, or run it up to ten times faster through the quiet parts.
- Review the trade in the journal, then go back to the entry and take it again.
The replay is described in more detail on the stock replay simulator page, and reading the book and the tape on the Level 2 and tape reading practice page.
Which days you can practise
Every trading day from August 2026 forward, and each new trading day is added overnight. Every stock, ETF and warrant listed on a US exchange is covered; OTC stocks are not. Chart history, filings and fundamentals reach back further than the days you can open.
The honest limits
Every fill is simulated. A marketable order fills against the displayed size in that day's book, best price first, and a limit order joins the back of the real queue at the exchange you route to, so a print at your price does not mean you were filled. Off-exchange and hidden liquidity never fill you, and your own order does not move the market after it fills. The full list of what the model does and does not capture is on the disclaimer page. A result here is a practice result: it says something about a decision against that day's book, not what the same decision would do with real money.
Common questions
- What is a day trading simulator?
- A platform where you place day trades with simulated money against market data, so you can practise entries, exits and risk without putting money at risk. Hindsight Markets uses real past market days, replayed as if they were live.
- Can you practice day trading without money?
- Yes. In a simulator every order is simulated and no order reaches an exchange or a broker. In Hindsight Markets you set your own starting balance, leverage and commissions, and nothing is connected to a real account.
- Is paper trading realistic?
- It depends on how fills are made. Here a marketable order fills against the displayed size in the real book and a limit order waits in the real queue, but off-exchange and hidden liquidity are not modeled and your order does not move the market. Treat results as practice, not a forecast.
- Is a day trading simulator good for beginners?
- It is a safe place to learn the mechanics: the order types, the hotkeys, how a halt or a short sale restriction works, and how fast a small cap moves. Starting at half speed gives you time to read Level 2 and the tape before you act.
- How do you practice day trading on small caps?
- Open a past morning, find a low-float stock on the gainers scan, plan the entry and the stop before you click, and trade it. Review it in the journal afterwards, then go back and take the same setup again until the decision is quick.
Practice day trading on a real past day
Pick a morning a small cap ran, and trade it as it happened with simulated money.