This page answers the most common questions traders ask before hiring an Expert Advisor programmer — from the basics of MetaTrader and MQL to hiring decisions, pricing, and how to avoid the mistakes we see in rescue projects every month.
MetaTrader & Expert Advisors
What is a MetaTrader Expert Advisor?
A MetaTrader Expert Advisor (EA) is an automated trading program that runs inside MetaTrader 4 or MetaTrader 5. It opens, modifies, and closes trades without manual intervention — based on coded rules that define entry signals, stop-loss placement, take-profit targets, and position sizing.
EAs range from simple single-indicator systems to complex multi-instrument robots with machine-learning filters and crash-resilient state management. At barmenteros FX, we have built hundreds of EAs across every complexity tier since 2011 — from $200 single-strategy robots to $2,500+ institutional-grade systems with custom license management.
See also: Expert Advisor Programming →
What is the difference between MT4 and MT5?
MetaTrader 4 and MetaTrader 5 are both trading platforms by MetaQuotes, but they are different programming environments — not just different versions. MT4 uses MQL4; MT5 uses MQL5. Code written for one platform does not run on the other without adaptation.
MT5 offers more order types, more timeframes, and a multi-threaded architecture that processes tick data faster. For new projects we recommend MT5 unless your broker supports only MT4 or your strategy is specifically designed around MT4’s order model.
We develop for both platforms and can migrate existing MT4 EAs to MT5 — though migration involves more than recompiling. See: MT4 Programmer Services →
What is MQL4 or MQL5?
MQL4 and MQL5 are the programming languages used to write Expert Advisors, indicators, and scripts in MetaTrader 4 and MetaTrader 5 respectively. Both are C-like languages with built-in trading functions for order management, price history access, and chart interaction.
MQL5 is more powerful but also more complex — it uses a true object-oriented model and has access to MetaTrader’s full multi-currency Strategy Tester framework. MQL4 has a simpler syntax and a massive library of existing EAs and indicators. Whether you need MQL4 or MQL5 depends on the platform your broker offers and the complexity of your strategy.
Can I run an Expert Advisor on any broker?
Not without testing first. EAs interact directly with your broker’s execution environment, and differences in spreads, commission models, stop-level requirements, and fill modes cause an EA to behave differently than it did in backtesting or on a different account.
We build EAs that account for common broker edge cases: floating-point precision in stop-loss calculations, minimum stop-distance enforcement, and instant-vs-market execution differences. We always recommend running any EA on a demo account with your target broker before going live — even when we built it.
Hiring an EA Developer
What does an Expert Advisor developer do?
An EA developer translates a trading strategy specification into production-ready MQL code. That means handling order logic, risk management, error handling for network interruptions and broker rejects, state persistence across terminal restarts, and verification that backtested behavior matches live execution.
Beyond writing code, experienced EA developers know how to avoid the traps that pass backtesting and fail in live markets: lookahead bias, incorrect tick handling, timezone mismatches in session filters, and broker-specific order routing quirks. Coding is the easy part; getting it right in production is the discipline.
Which type of programmer do I need — MT4, MQL5, EA, or Forex?
These are all names for the same role. Whether someone calls themselves an MT4 programmer, MQL4 developer, EA developer, Forex programmer, or algo-trading developer — they are doing the same job: writing automated trading programs for MetaTrader.
The label varies by region and how developers market themselves. What matters is whether they have production experience on live accounts with real brokers, not which label they use. Ask for examples of EAs they have built and whether those EAs ran on real money.
How do I find a reliable EA developer?
Focus on three signals: evidence of live trading experience (not just demo backtests), transparent fixed-price quotes rather than open-ended hourly rates, and a written project specification before any work begins.
Reliable developers ask detailed questions about your strategy before quoting. If a developer names a price before understanding your requirements, treat that as a warning sign. At barmenteros FX, every project starts with a requirements review — we do not write code until we understand exactly what you need and you have agreed to a fixed price.
I was cheated by an EA developer before. How can I avoid it again?
This is the most common concern we hear from new clients. After 14 years in this market we recognise the patterns: developers who take payment and disappear, deliver non-functional code, or claim it worked on their demo account.
Protect yourself by: verifying the developer is a real business with an independently verifiable track record; requiring a written specification before paying; using a payment platform with buyer protection (PayPal, Stripe) for your first engagement; and confirming the developer offers a support period after delivery — not just the file. We are an EU-registered business with a public profile on MQL5.com.
Working with barmenteros FX
How much does custom EA development cost?
Simple single-strategy EAs start at 200. Projects with multiple entry conditions, advanced risk management, or session filters typically range from $400 to $2,500 depending on scope. Complex systems — multi-symbol logic, machine-learning integration, or crash-resilient state management — reach the upper end.
We quote fixed prices, not hourly rates. You know the cost before we start. Quotes are issued within 48 hours of receiving your specification. All prices are in USD.
How long does EA development take?
Simple EAs: 2–5 business days. Standard projects with multiple conditions and risk modules: 1–3 weeks. Complex systems — multi-symbol, ML integration, custom state management: 3–6 weeks.
Timeline depends on scope, revision cycles, and the clarity of the initial specification. A well-written specification reduces development time by 30–50%. Projects that begin with vague requirements take significantly longer, not because of delays on our side, but because clarification cycles could have been resolved before the first line of code.
What platforms do you develop for?
We develop for MetaTrader 4 (MQL4), MetaTrader 5 (MQL5), TradingView (Pine Script), NinjaTrader (C#), cTrader (cAlgo), and MultiCharts (EasyLanguage). We also build Python-to-MetaTrader bridge integrations for strategies that require external data feeds or machine-learning model outputs.
See the full list: Our Services →
Do you also build custom indicators and scripts?
Yes. Custom indicators, scripts, and utility tools are a separate service alongside EA development. We build indicators for MetaTrader 4 and MT5 — oscillators, market structure tools, volume analysis, custom drawing objects — as well as one-click scripts and semi-automated tools that do not manage positions independently.
Custom indicator projects start at $150, with most single-indicator builds ranging from $150 to $600. Complex multi-indicator dashboards or real-time data integrations reach up to $1,200. All indicator work follows the same process as EA development: written specification, fixed price, no code until you have agreed to the quote.
See: Custom Indicator Development →
Making Your EA Reliable
Can I trust a free Expert Advisor I found online?
Treat free EAs with caution. Most fall into one of three categories: promotional tools designed to get you to open a specific brokerage account; poorly tested code that produces strong backtest results through data-fitting; or early-generation code that has not been maintained as broker execution environments evolved.
This does not mean all free EAs are worthless — simple utility scripts and educational examples can be legitimate. But for any strategy you plan to run on real money, a professionally built and independently tested EA significantly reduces the failure modes we see in EA rescue projects every week.
Why do EAs fail in live trading when backtesting looked profitable?
The four most common causes: lookahead bias (the backtest uses price data the EA could not have seen at signal time), spread assumptions (backtests often use a fixed spread that does not match your broker’s variable spread), execution model mismatches (instant vs. market execution fill behavior), and timezone errors in session filters.
In over 14 years of client work, we have diagnosed all of these. The EA with a 90% backtest win rate that loses on its first live trade almost always has one of these four problems. We identify and document them in every EA we build or review.
See also: EA Debugging & Code Review →
How can I protect my EA from unauthorised copying?
MetaTrader allows you to compile EAs into an .ex4 (MT4) or .ex5 (MT5) binary that cannot be read as source code. This prevents casual copying but does not prevent determined decompilation attempts.
For stronger protection, we offer LicenseShield — our EA license management system that locks your EA to specific broker account numbers, controls access programmatically, and supports trial and commercial distribution without exposing your source code. You can revoke licenses, set expiry dates, and sell EAs independently.
Learn more: LicenseShield — MT4/MT5 License Management →
Ready to Get Started?
Have a strategy you want automated? We have been building production-grade Expert Advisors since 2011. Tell us what you need — we will review your requirements and send a fixed-price quote within 48 hours.