barmenteros FX builds custom Expert Advisors for MetaTrader 4 and MetaTrader 5. From strategy specification to production-ready MQL4/MQL5 code, we deliver EAs that handle broker edge cases, state persistence, and real-market conditions — not just backtests that look good on paper.
Not sure what an Expert Advisor can do for your strategy? Read our complete guide to Expert Advisors — what they are, what functions they cover, and the three ways to get one.
What You Get
- Production-ready compiled files — .ex4 or .ex5 tested against your target broker environment
- Full source code — .mq4/.mq5 files you own completely, with no licensing restrictions
- Backtest validation — Strategy Tester reports verifying core logic before delivery
- Input documentation — parameter descriptions, recommended settings, and known limitations
- Deployment support — assistance during initial live setup on your VPS or terminal
How It Works
- Specification — You describe your trading rules, risk parameters, instruments, and timeframe. Not sure how to document your strategy? Our [guide to writing EA specifications that save money](/specification-saves-money-ea-project/) walks you through it.
- Review & Quote — We evaluate complexity and provide a fixed-price estimate within 48 hours. No hourly billing.
- Development — We build, test, and iterate. You receive progress updates and backtest results at each milestone.
- Delivery & Verification — Compiled files, source code, and backtest reports delivered. We support your initial deployment and answer questions during the first live sessions.
What Is an Expert Advisor?
An Expert Advisor — also called an EA, trading EA, or Forex robot — is a program written in MQL4 or MQL5 that runs inside the MetaTrader 4 (MT4) or MetaTrader 5 (MT5) trading platform. Unlike manual trading, an EA monitors the market continuously, evaluates pre-defined conditions, and acts on them without waiting for a human decision.
The idea is simple: you define a trading strategy — entry rules, exit rules, position sizing, risk management — and the EA executes it consistently, 24 hours a day, without fatigue or emotion. The strategy is designed by you; we translate it into code the MetaTrader platform runs reliably.
Expert Advisors work on any instrument available through your broker’s MetaTrader terminal:
- Forex currency pairs (EURUSD, GBPUSD, USDJPY)
- Cryptocurrencies (Bitcoin, Ethereum, Ripple)
- Commodities (Gold, Oil, Corn)
- Indices, Bonds, Stocks, and ETFs
The range of tradeable instruments depends on what your broker offers in their MetaTrader server configuration.
What an Expert Advisor Can Do
An Expert Advisor can handle every aspect of trade management autonomously. The most common functions:
- Market monitoring — continuously scanning price action, indicator values, and conditions against your strategy’s rules.
- Order execution — opening buy or sell positions the moment conditions trigger, not when you happen to check your charts.
- Position management — modifying stop-loss levels, take-profit targets, and trailing stops as the market moves.
- Risk control — calculating position sizes based on account balance, equity, or a fixed risk percentage per trade.
- Partial closes — closing part of a position at a profit target while letting the rest run.
- Alerts and notifications — push notifications, emails, or on-screen alerts on specific market events.
In our experience building EAs since 2011, the most requested combination is automated entry with dynamic position sizing and trailing-stop management — roughly 70% of the custom EA projects we deliver.
Standard Features Every EA Should Have
These belong in every production-quality Expert Advisor. If an EA lacks them, it will cause problems in live trading:
- Run once per bar — execute logic on every tick or only at the open of each new bar. Without this control, an EA wastes processing power and can fire unexpected multiple entries.
- Separate instances — run on multiple charts at once, even on the same pair, alongside other EAs and manual trades, with each instance tracking its own positions independently.
- Retry on error — when the broker returns a server error, requote, or timeout, the EA retries before giving up. Network hiccups are normal in live trading.
- Automatic stop adjustment — if a stop-loss, take-profit, or pending price triggers an “invalid stops” error, the EA adjusts to the closest valid level based on the broker’s minimum stop distance, preventing rejection in volatile conditions.
A common pattern we see in rescue projects: EAs that work perfectly in backtesting but fail on the first live trade because they don’t handle broker error codes. Error handling is not optional — it is the difference between a demo toy and a production trading system.
Optional Features for Advanced EAs
These can be added to any Expert Advisor based on your strategy. Each is a standard building block our team integrates during development:
- Money management — adjusts lot size from a risk percentage of equity or balance (requires a stop-loss on every order to size correctly).
- Martingale lot sizing — increases lot size after consecutive wins or losses via an adjustable multiplier (fixed, Fibonacci-based, or capped progression).
- Trailing stops — activate after a profit threshold; the stop follows price at a set distance, optionally in fixed pip steps.
- Break-even stop — moves the stop to entry (plus optional locked-in pips) once a profit target is reached.
- Daily timer — restricts trading to specific hours and minutes, for session-based strategies or avoiding news.
- Block timer — custom start/end windows; multiple timers can block trading around volatile scheduled events.
- Spread protection — suspends trading when the spread exceeds a maximum, essential for variable-spread pairs in low liquidity.
- Margin check — suspends new orders when used margin exceeds a set percentage, preventing unexpected margin calls.
This is not exhaustive. Almost any trading logic can be coded into an EA — if you can define the rules precisely, we can build it.
Who This Is For
Good fit:
- Traders with a defined strategy who need reliable automated execution on MetaTrader
- Developers stuck with AI-generated or freelancer code that fails on anything except EURUSD
- Firms migrating MT4 systems to MT5 and needing production-grade architecture, not just recompilation
Not the best fit:
- No clear trading strategy yet — we build execution tools, not trading strategies
- Budget under $200 — quality EA development requires thorough testing and broker-specific handling
- Expecting profit guarantees — no honest developer can promise that
What Makes This Different
Since 2011, barmenteros FX has built and maintained Expert Advisors across dozens of broker environments. That experience surfaces in production details most developers never encounter: how an EA handles broker disconnections mid-trade, why state persistence matters when a VPS reboots during a recovery cycle, or how floating-point precision differences between MT4 and MT5 affect multi-symbol calculations.
Roughly 40% of our projects are rescue work — clients bring us EAs built by other developers that technically “work” but fail their first live stress test. These rescues have taught us where the real failure points are: not in entry logic, but in error handling, execution timing, and whether to fix or rebuild. We apply those lessons to every new build.
We test against production constraints: broker-specific stop levels, variable spreads during news events, and the behavioral differences between hedging and netting accounts. Every EA we deliver is hardened for these conditions before shipping.
Ways to Get an Expert Advisor
There are three paths to getting an EA, with trade-offs in cost, flexibility, and strategy complexity.
Learn MQL4 or MQL5 yourself. MetaTrader includes MetaEditor and a wizard for basic EAs. The wizard handles simple strategies built on standard indicators; anything more — multi-timeframe logic, custom entries, advanced risk management — needs hand-written code. Beyond programming, you’ll need a solid grasp of lot sizing, risk management, and the MetaTrader order system. It’s a significant time investment.
Use an EA builder. Visual, no-code tools (usually paid) work for simple to moderately complex strategies. They hit a ceiling fast: custom logic, multi-instrument correlation, advanced state management, and broker-specific edge cases typically require code.
Hire a professional developer. If you have a strategy and want it implemented correctly the first time, hiring a professional MT4/MT5 programmer is the most reliable path — production-ready code that handles error conditions, broker constraints, and the edge cases builders and tutorials skip. This matters most for strategies spanning multiple instruments, complex position management, or any logic that must survive connection drops and terminal restarts.
Pricing
Simple single-strategy EAs start at $200. Standard projects with multiple instruments, advanced risk management, or crash-resilient state persistence typically range from $400–$2,500 depending on scope.
We quote a fixed price after reviewing your specification. No hourly billing, no scope surprises.
Frequently Asked Questions
How much does custom Expert Advisor programming cost?
Simple single-strategy EAs start at $200. Standard projects with multiple instruments or advanced risk management typically range from $400–$2,500. The final price depends on strategy complexity, number of instruments, and whether the EA needs crash-resilient state persistence. At barmenteros FX, we provide a fixed-price quote within 48 hours of reviewing your specification — no hourly rates or hidden fees.
How long does EA development take?
Typical timelines range from 1–2 weeks for straightforward single-strategy EAs to 4–8 weeks for complex multi-instrument systems. The largest variable is specification clarity — detailed trading rules with explicit entry/exit conditions let us start immediately. Vague specifications require clarification rounds that add time.
Can I develop an Expert Advisor myself?
MetaTrader includes MetaEditor, a free IDE for [MQL4](/mql4/) and MQL5 development. The MQL5.com documentation and community forums provide solid learning material. Self-development works well for simple indicators and scripts. For strategies you’ll trade with real capital, the challenge is production reliability — an EA that passes backtests may fail live due to execution delays, broker stop levels, or over-optimization that makes it worse, not better. Professional development eliminates the gap between “compiles” and “survives live markets.”
What information do I need to provide?
A strategy specification covering: entry and exit rules, risk management parameters (lot sizing, stop loss, take profit), instruments to trade, and preferred timeframe. The more detail you provide, the faster and more accurately we build. If you’re unsure how to document your strategy, our specification guide explains exactly what to include.
Do I own the source code?
Yes. You receive both compiled .ex4/.ex5 files and full MQL4/MQL5 source code. You own it completely — modify it, hire another developer to extend it, or use it as the basis for future projects. We do not retain rights or insert licensing restrictions into client code.
What is the difference between an Expert Advisor and an indicator?
An indicator analyzes price data and displays visual information on the chart — moving averages, oscillator levels, signal arrows. It does not execute trades. An Expert Advisor reads market data (and can use indicator values as input), makes trading decisions, and executes orders automatically. The indicator is the analyst; the EA is the trader that acts on the analysis.
Can an Expert Advisor trade multiple currency pairs simultaneously?
Yes, but the approach matters. The simplest, most reliable method is one EA instance per chart, each managing its own symbol independently. The alternative — one instance managing several symbols from an internal list — adds significant complexity (40–60% more development effort) and is only needed for strategies requiring real-time cross-pair correlation.
Are Expert Advisors profitable?
An Expert Advisor executes a trading strategy — it does not create one. If the underlying strategy is profitable under real market conditions, the EA executes it consistently; if the strategy is flawed, the EA loses consistently. Profitability depends on the quality of the trading logic, not the EA itself. Always validate backtest results with forward testing on a demo account before risking real capital.
Do Expert Advisors work the same on MT4 and MT5?
Both platforms support EAs, but MQL4 and MQL5 are significantly different. An EA written for MT4 cannot run on MT5 without being rewritten — not just recompiled. The order management system, position-tracking model, and many built-in functions changed between platforms. Moving an EA from MT4 to MT5 requires a proper migration, not a simple port.
Related Services
- EA code review — what we find inside “working” Expert Advisors
- MT4 to MT5 migration — why recompiling is the easy part
- Protect your EA’s intellectual property with LicenseShield
- Expert Advisors explained — what they are, what they do, and how to get one
- New to EAs? Step-by-step install guides for MetaTrader 4 and MetaTrader 5