Practice without risk: replay and backtesting

Professional athletes practice far more than they play. Traders can too. Replay and backtesting let you practice a setup dozens of times in a week, without risking a dollar.

What market replay is

Market replay plays back a past trading session tick by tick, as if it were live. You can pause, speed up or slow down. Most futures platforms offer replay, including NinjaTrader and Tradovate.

Because you do not know what happens next, replay feels much closer to live trading than looking at an old chart. You still have to make decisions in real time.

Backtesting vs replay

• Backtesting looks at historical charts to see how a setup would have performed. It is fast and good for a first look.
• Replay makes you trade the setup in simulated real time. It is slower and better for building skill.

Use backtesting to decide if a setup is worth practicing. Use replay to practice it.

How many trades is enough?

A handful of trades tells you almost nothing. Even a great setup can lose 4 times in a row. Take 20 to 50 samples before you judge it. The more samples you have, the more you can trust the numbers.

What to track

• Win rate: winning trades ÷ total trades
• Average win: total won ÷ number of winners
• Average loss: total lost ÷ number of losers

Together these show whether the setup makes money over time. A 45% win rate with an average win twice the size of the average loss is a healthy result, as you saw in lesson 11.

A simple replay routine

1. Pick 1 setup and write its rules down.
2. Choose a random past date. Avoid looking at that day's chart first.
3. Mark your levels as if it were that morning.
4. Play the session and trade only your setup, with your normal size and stops.
5. Record every trade in your journal (lesson 17).
6. Repeat until you reach 20 trades, then review the numbers.

Be honest with yourself

Replay only helps if you follow your rules. Skipping losing trades, moving stops or peeking ahead makes the results look better and teaches you nothing. Treat every replay trade like real money.