How to hire an MQL5 developer: checklist and red flags
Most problems with a custom Expert Advisor are decided before a line of code is written: by what was agreed, what was tested and who owns the result.
QuantFX7 min read
Before you contact anyone
Write your strategy down. One or two pages is enough: when the EA enters, when it exits, how it sizes positions, what it does with an open trade, and what stops it trading. Include the platform (MT4 or MT5), the symbols, the timeframe and your broker. A developer who receives this can give you a real quote. A developer who receives "I want a profitable gold scalper" can only guess.
The checklist
1. Do you get the source code?
Ask for the full .mq5 or .mq4 source code, not only the compiled .ex5 or .ex4 file. Without the source you cannot fix a bug, adapt the EA to a new broker, or move to another developer. Some developers lock EAs to an account number or a licence server; make sure you know before you pay.
2. Is there a written specification?
A good developer turns your description into a specification and asks you to confirm it before starting. It should list every rule in exact terms, including the edge cases: what happens on a gap, when the spread is wide, when an order is rejected, or when the terminal restarts with a trade open. The specification is what the work is checked against, and what decides whether a change is a bug fix or a new request.
3. How will the EA be tested?
Ask what testing is included. At a minimum: runs in the MT5 strategy tester on real tick data, with variable spreads and your broker's costs, and a check that each rule in the specification behaves as written. Better still, a forward test on a demo account at your broker, so live execution is tested before real money is involved. Ask to see the reports.
4. Do they understand live execution?
Many EAs work in the tester and fail live. Ask how the developer handles requotes, partial fills, broker stops-levels and freeze-levels, slippage, symbol suffixes such as XAUUSD.m, and lot-size normalisation. A developer who has run EAs on live accounts will have clear answers.
5. What happens after delivery?
Agree how long bugs are fixed for free, how quickly the developer responds, and how changes are priced. Strategies evolve; you will almost certainly want changes after a few weeks of trading.
6. Can they show relevant work?
Ask for examples of similar EAs, indicators or fixes. Code samples and tester reports are more useful than screenshots of profits. Be cautious about developers whose main selling point is their own trading results.
7. Who are you dealing with?
Know whether you are hiring an individual or a company, where they are based, and how disputes are handled. On a marketplace, the platform's escrow and arbitration rules apply; with an agency, the contract does.
Red flags
- Promises of profit, a guaranteed win rate or passing a prop firm challenge.
- No source code, or source code only for an extra fee after the fact.
- No questions about your rules before quoting.
- A finished EA delivered in hours with no tester reports.
- EAs locked to the developer's server or licence key with no exit.
- Requests for your trading account password or access to your funds.
- Backtests with fixed spreads and no costs presented as proof.
Freelancer, marketplace or agency?
Freelance marketplaces such as MQL5 Freelance, Fiverr or Upwork are the cheapest route, with escrow to protect payment. Quality varies widely, and testing and support are usually minimal unless you specify them. They suit small, well-defined jobs.
Independent developers you find directly can be excellent, but you rely on one person for availability and support.
A development company costs more, but usually brings a written process, testing, documentation and continuity if one person is unavailable. It suits EAs you plan to run on real money for a long time, prop firm accounts, and anything that needs integration with other systems.
Questions to ask in the first conversation
- Will I receive the full source code?
- Will you write a specification for me to confirm before you start?
- What testing is included, and will I see the reports?
- How do you handle spreads, slippage and rejected orders?
- How long are bug fixes included after delivery?
- How are later changes priced?
- When will it be delivered?
For what drives the price of the work, see how much a custom Expert Advisor costs.
How we work
At QuantFX every EA project starts with a written specification and a fixed quote, and ends with the full source code, real-tick tester reports, a demo forward test and bug-fix support. We also take on MQL5 porting, audits and fixes for existing code. See custom MT5 Expert Advisor development for the full process.
Trading leveraged products carries a high risk of loss. This article is general information about hiring software developers, not investment advice.