MT4 vs MT5 EA Development — Which Platform Should You Choose in 2026?
MT4 still dominates broker offerings. MT5 is technically superior. If you're building an Expert Advisor, the platform you choose determines your code architecture, available functions, and broker compatibility. Here's the complete technical comparison.
Code Architecture — The Biggest Difference
| Feature | MT4 (MQL4) | MT5 (MQL5) |
|---|---|---|
| Order execution | OrderSend() with 11 parameters | CTrade.PositionOpen() — cleaner |
| Position tracking | OrdersTotal() + OrderSelect() loop | PositionsTotal() + PositionSelectByTicket() |
| Indicators | Called as functions: iRSI(), iMA() | Handle-based: iRSI() creates handle, CopyBuffer() reads |
| Market data | MarketInfo(Symbol(), MODE_*) | SymbolInfoInteger/Double() |
| Account | AccountBalance() | AccountInfoDouble(ACCOUNT_EQUITY) |
| Backtesting | Single-thread, 32-bit | Multi-thread, 64-bit, real tick data |
| Order types | 6 types (OP_BUY/SELL/LIMIT/STOP) | ORDER_TYPE_BUY/SELL + LIMIT/STOP/STOP_LIMIT |
| Hedging | Built-in | Requires hedging account type |
| ONNX / ML | Not available | Native ONNX model support |
| Broker adoption | Wider — still 60%+ of brokers | Growing rapidly |
Which Platform Should You Choose?
Choose MT5 if: You want modern architecture, better backtesting, ONNX/ML capabilities, multi-currency testing, and your broker supports it. MT5 is the future — MetaQuotes stopped selling new MT4 licenses.
Choose MT4 if: Your broker only offers MT4, you need hedging (MT5 hedging accounts are less common), you have legacy MQL4 code to maintain, or you trade with a prop firm that only supports MT4.
Our recommendation: Build for both. Use our MT4 EA Builder and MT5 EA Builder to generate platform-specific code from the same strategy. Both are free, no signup required.