Pine Script vs MQL5: why a TradingView strategy behaves differently on MT5
By Praveen Divvala · · 4 min read
Short answer
A TradingView Pine Script strategy will not behave identically as an MT5 Expert Advisor because the platforms process bars and orders differently, use different data feeds, and treat costs such as spread differently. Converting means rewriting the logic in MQL5, then comparing signals against the original chart to confirm they match.
Different execution models
Pine Script strategies run on chart bars and, by default, simulate orders filling at the next bar. An MT5 Expert Advisor is event-driven and reacts to each incoming tick, sending real orders to a broker. The same rule can therefore fill at a different price or time.
Repainting indicators
Some indicators change their past values as new bars form. On a chart the history looks perfect, but a live signal that later disappears cannot be traded. Repainting should be identified before converting, and the EA should be told exactly how to treat it.
Data feeds and broker differences
TradingView and your MetaTrader broker each use their own price data. Candle highs, lows and timestamps can differ slightly, and small differences can flip a signal on a borderline bar.
Costs and order handling
A live MetaTrader account has spread, commission, slippage and minimum lot sizes. Order types, stop levels and partial closes are also handled through the platform’s own rules. These realities are missing from a simple chart simulation.
How a good conversion is done
The logic is re-implemented in MQL5 or MQL4 instead of being pasted across. Signals are then compared bar by bar against the TradingView chart, and any differences are explained. Risk management such as stop-loss, take-profit, trailing and position sizing is added so the EA is safe to run automatically.
General information about software and trading platforms, not investment advice. Trading leveraged products carries a high risk of loss. See the risk disclosure.