GLOSSARY · METATRADER
What is Strategy Tester?
The Strategy Tester is MetaTrader's built-in backtesting and optimisation engine, which replays historical data through an EA to estimate how it would have performed.
What it means
MT5's tester supports several modelling modes, from open prices only through to real ticks. The differences are enormous — a strategy that looks profitable on open prices frequently collapses under real tick modelling, because the cheaper modes never test what happened inside the bar.
Why it matters
Optimisation, which sweeps parameter ranges to find the best-performing combination, is the tester's most dangerous feature. Running thousands of combinations guarantees that some will look excellent on the sample by chance, and selecting the best is a highly efficient way to produce an overfitted system.
What this changes in practice
Our own testing does not use the Strategy Tester at all. We replay real broker bars through the same signal code the live engine runs, with the real tracker driving strategy selection, so there is no separate backtest implementation that could diverge from live behaviour. Reimplementing the strategy for testing is a common and invisible source of false results.
Related terms
- BacktestingBacktesting runs a strategy against historical data to estimate how it would have performed, and…
- OverfittingOverfitting is tuning a strategy so closely to historical data that it captures the noise of tha…
- Modelling qualityModelling quality is the Strategy Tester's estimate of how faithfully it reconstructed price mov…
- Out-of-sample testingOut-of-sample testing evaluates a strategy on data deliberately withheld during development, to …
Educational information only, not financial advice. Trading leveraged products carries substantial risk of loss. Last updated 2026-08-11.