I am considering buying an EA

[Fidan Tahiri]

Hello,

I am considering buying an EA and I have an important technical question before making the purchase.

Is it technically possible for an EA to be programmed to perform very well in the Strategy Tester/backtest, but behave differently or perform much worse on a real/live account?

For example, could the EA contain some mechanism that detects when it is running in the Strategy Tester and uses different logic during backtesting, or otherwise manipulates/fakes the backtest results?

If this is technically possible, what are the main ways a developer could do this, and how can a buyer detect or verify it before purchasing the EA?

Also, if the EA is provided only as a compiled EX5 file and the MQ5 source code is not provided, is there any reliable way to verify that the backtest results have not been manipulated?

I would appreciate any technical advice from experienced MQL5 developers.

Thank you.

[Evgeniy Ilin]

Fidan Tahiri:

Hello,

I am considering buying an EA and I have an important technical question before making the purchase.

Is it technically possible for an EA to be programmed to perform very well in the Strategy Tester/backtest, but behave differently or perform much worse on a real/live account?

For example, could the EA contain some mechanism that detects when it is running in the Strategy Tester and uses different logic during backtesting, or otherwise manipulates/fakes the backtest results?

If this is technically possible, what are the main ways a developer could do this, and how can a buyer detect or verify it before purchasing the EA?

Also, if the EA is provided only as a compiled EX5 file and the MQ5 source code is not provided, is there any reliable way to verify that the backtest results have not been manipulated?

I would appreciate any technical advice from experienced MQL5 developers.

Thank you.

Few people will give you an honest answer here in public, but I can.

First of all, the Strategy Tester is merely a tool for the developer, and at the same time, a showcase for buyers. To some extent, all robots look better in backtests than they do in live trading. If you follow that logic, then every robot on the market is falsified. Including mine.

But the truth always lies somewhere in the middle. The outcome of your decision is, first and foremost, a symbiosis of your knowledge, pragmatism, and sense of reality. Good luck with your choice.

[Sergey Golubev]

About my personal experience -  I am posting it all the time on the forum during the many years
(it is about Market products but it is same for the Signals and for Freelance as well):

Forum on trading, automated trading systems and testing trading strategies

...

Sergey Golubev, 2021.01.14 09:18

• If you bought the product from your friend or from your relative or from very active users on this forum so you can fix anything related with the sellers who are responsible about what they are selling (and because you both know each other for the long time).
• But if you bought something from "anyone" just because you have a lot of money so - sorry:
  it is your risk, and this risk can not be turned to anyone else.

----------------

I am posting this suggestion all the time on the forum. It is related to the Signals, the Market, and to the Freelance as well - 

Forum on trading, automated trading systems and testing trading strategies

...

Sergey Golubev, 2020.01.16 06:35

There is one rule which some people follow:
subscribe to the signal or create an order in Freelance or purchase the product from the user/seller/coder/provider you know in person or you know by activity on the forum.

Because if you purchased something so I may ask:
"Do you know the seller in person, or you are familiar with him on this forum?"
If you say: "Not" so it will be very strange case for me ...

Just my optinion.

----------------

There are a lot of professional and honest users/coders on the forum, and some of them are very active on this forum helping to the other people and replying on the forum posts/requests.

Always choose the person you know in this forum (who is very active here), and you will have less problems with anything.

Just my opinion sorry.

[Ryan L Johnson]

Fidan Tahiri:
Is it technically possible for an EA to be programmed to perform very well in the Strategy Tester/backtest, but behave differently or perform much worse on a real/live account?

For example, could the EA contain some mechanism that detects when it is running in the Strategy Tester and uses different logic during backtesting[?]...

If this is technically possible, what are the main ways a developer could do this[?]...

Yes. An EA can easily detect whether it's running in the Tester. Therefore, different code can be conditionally run following that detection.

Forum on trading, automated trading systems and testing trading strategies

Can EA detect if it's in Test Strategy?

Icham Aidibe, 2018.02.09 01:21

Yes.

if (MqlInfoInteger(MQL_TESTER)) { printf("*** tester"); }

There's also a visual mode property ...

https://www.mql5.com/en/docs/check/mqlinfointeger

Fidan Tahiri:
[H]ow can a buyer detect or verify it before purchasing the EA?

Not possible without source code.

As a side note, retail CFD and FX instruments are priced in-house by an individual broker-dealer and indirectly, by its partnered "liquidity providers"─investment banks, hedge funds, etc. The price that you get is the price that the broker-dealer decides to give you. There is no centralized exchange, equal price discovery, nor equal execution priority─unlike trading in the Chicago Mercantile Exchange, for example. Therefore, EA performance can and will differ across different CFD/FX broker-dealers. IMHO, every CFD/FX trading EA for sale in the Market should disclose the individual broker-dealer with which the EA was tested on live data.

https://www.mql5.com/en/blogs/post/771848