Why platform choice matters more for EA traders than for manual traders
For a manual trader, MT4 vs MT5 is a question of habit and chart comfort. For an EA trader, the platform decides backtest quality, execution architecture, multi-symbol capability, and the long-term viability of the code. Anyone developing today is making a decision that will have consequences for years.
At a glance
| Criterion | MT4 | MT5 |
|---|---|---|
| EA language | MQL4 | MQL5 |
| Tick data | Broker-supplied, limited | Genuine tick download, high quality |
| Backtesting | Single-threaded, slow | Multi-threaded, dramatically faster |
| Account model | Hedging (multiple trades per symbol) | Netting (default) + hedging option |
| Multi-asset | Limited (no native futures) | Stocks, futures, options, forex |
| Development status | Discontinued (no active updates) | Actively developed |
| Broker availability | Very high (nearly all forex brokers) | 17 of 18 reviewed brokers (all except IG) |
| Community / EAs | Huge legacy library | Growing, more modern library |
Account model: the most overlooked difference
This is the point that surprises most switchers.
MT4 — hedging model: you can hold multiple independent long and short positions on the same symbol simultaneously. Each position has its own SL, TP, and trade history entry. For multi-EA setups where EA A is long and EA B is short on EURUSD, this is intuitive.
MT5 — netting model (default): positions on the same symbol are merged into a single net position. A long and a short on EURUSD partially cancel each other out. This changes how EAs must implement their position management logic.
MT5 with hedging account: since MT5 build 1755+, many brokers offer MT5 accounts in hedging mode. This resolves the problem — but check whether your broker supports it. Our broker reviews document which account models each provider offers on MT5.
MQL4 vs MQL5: what changes when developing?
MQL5 is very similar to MQL4 but not identical. The key differences for EA developers:
Position management: in MQL4 you work with OrderSend(), OrderSelect(), and a simple order pool. In MQL5 there is PositionSelect(), PositionGetDouble(), and the CTrade class from the standard library — more powerful, but structured differently.
Type strictness: MQL5 is more strictly typed. Code that works in MQL4 with implicit casts will not compile in MQL5 without explicit conversions.
Object model: MQL5 has a fully object-oriented standard library (CTradeClass, CIndicator, etc.) that considerably simplifies professional EA design.
Indicator buffers: indicators work differently in MQL5 — iCustom returns a handle rather than a direct array value. The switch takes time to internalise but is more consistent once learned.
Backtesting: MT5 is clearly superior
This is the uncontested advantage of MT5 for EA developers.
Genuine tick download: MT5 downloads tick-by-tick data directly from the broker. Quality depends on the broker but is significantly better than MT4's interpolated ticks for most modern MT5 brokers.
Multi-threaded optimisation: MT5 uses all available CPU cores for optimisation runs. What takes hours in MT4 is done in minutes in MT5.
Walk-forward analysis: MT5 includes a built-in walk-forward optimiser. In MT4 you need third-party tools.
For rigorous backtesting and forward-testing, MT5 is the considerably better platform.
Broker availability: the MT4 argument is gone in 2026
For years this was the strongest practical argument for MT4. It no longer holds: practically every broker in our broker reviews offers both MT4 and MT5, including IC Markets, IC Trading, RoboForex, BlackBull, Pepperstone and XM. Many add cTrader or TradingView on top. Anyone opening an account today gets MT5 almost everywhere. The exception in our reviews is IG: it offers MetaTrader only as MT4, with its own algos running via ProRealTime and the API.
What actually runs: figures from our EA park and the review hub (as of September 2026)
Two data sets we maintain ourselves:
| Source | MT4 | MT5 | both |
|---|---|---|---|
| 118 commercial EAs in the EA review hub | 6 MT4 only | 27 MT5 only | 83 |
| 58 terminals in our own EA park | 15 | 43 | – |
Of the 118 EAs in the review hub only 6 are still MT4-only, 27 are MT5-only and 83 ship for both; the rest are copy-trading offers or carry no platform label. In our park three out of four terminals run MT5; the MT4 terminals are almost all legacy for EAs we have operated since 2024. That is not ideology but convenience: on MT5 the tester loads real ticks, optimisation uses every core, and broker builds arrive without asking.
VPS and runtime environment
Both platforms run on a Windows-based VPS. MT5 is more resource-intensive than MT4; with multi-chart setups running many EAs, factor this into your RAM planning. A practical rule of thumb: MT4 with 5–10 active charts is comfortable at 2 GB RAM; a comparable MT5 setup wants closer to 4 GB. From our park: a 4 GB server carries five MT5 terminals stably, the 32 GB hubs run 14 to 15 terminals. The cheapest entry into a broker data centre right now is Hyonix with 2 vCore and 4 GB for $12 a month, Equinix NY4 selectable; all providers are in the forex VPS comparison.
Which platform for which use case?
Choose MT4 if:
- You are running a proven commercial EA that is only available for MT4.
- Your broker only offers MT4.
- You have a large existing MQL4 codebase you are not ready to port.
Choose MT5 if:
- You are developing something new or porting existing strategies.
- You run serious walk-forward tests and multi-pass optimisations.
- You want to trade multi-asset or futures.
- You want platform security for the long term.
Conclusion
MT4 is the legacy; MT5 is the future. For all new EA development and for serious backtesting, MT5 is the better choice today — superior test infrastructure, better tick data, and active ongoing development. The only substantive argument for MT4 is the legacy EA library — broader broker availability stopped being one in 2026. Anyone active in algo trading for the long term will eventually need to port their strategies to MT5.