Expert Advisors – EA – Automatic trading system

Others informations :

  1. About Expert Advisors
  2. About MQL4 language
  3. About VPS – Virtual Private Server

What is an Expert Advisor (EA) ?

An Expert Advisor (or EA) is a script used by the trading platform (most often on MetaTrader 4) to manage the positions and the take of orders automatically without manual intervention.

You can then configure an Expert Advisor dealing independently on your account. This EA is merely carrying out the parameters which have been given and it is the validation of these parameters which allows it to enter / exit / place orders on your trading account. The EA can be very simple or very complex. It may be based on a single parameter (eg an indicator), or have a multitude of parameters.

An Expert Advisor is running on a chart. In reality this is as if the EA was watching your charts continuously and drew conclusions with parameters that have been set. You will understand then logically it is essential that indicators be included on the chart. So you can set for example the Expert Advisor to open a long position when the indicator is bullish; ordering him to cut the long position and go short when the indicator returns downward. This is one example. The Expert Advisor can of course set the stop loss protection, the take profit, and hours of system activation, and more …

The best way to become familiar with the concept of Expert Advisor is to test one on a demo account. There are multitudes of EA on the Internet (free or not). As much EA is possible that the combination of indicators and parameters possible.

Basically, your platform MetaTrader 4 makes normally available two Expert Advisors: one based on the MACD and the other on moving averages. You will find this EA in the window “Navigator” from your platform in the tab “Expert Consultant”.

Metatrader 4 Expert Advisors

Launch an expert advisor

Step 1: Open your platform and select a chart and a TimeFrame on which you want the EA to be applied (You must not change the timeFrame once the EA started. You will risk asking him to reopen a position based on new criteria of the new TimeFrame). So select the right TimeFrame in the bar underneath the menus:

Metatrader 4 Expert Advisors

Step 2: Select an EA in the window “Navigator” and drag the mouse over the chart. A pop-up window will appear (such as that presented to you below).

In the first tab (common), it is important to select ‘Allow live trading’ or your EA will not pass any order.

Metatrader 4 Expert Advisors

The tab “Input parameters” allows you to configure your EA with all the settings you have chosen to assign to the EA. So in that window you set level of stop loss, take profit and other of the EA and others.

Metatrader 4 Expert Advisors

Click on OK.

Step 3: If the EA has been well affected to your chart, you should see the top right of your chart with a smiley with the name of the EA.

Metatrader 4 Expert Advisors

If the smiley is a smile, your EA works and start making orders when conditions implemented in its logic will be met.

If the smiley does not appear but a small cross is displayed, you must allow the use of Expert Advisors at the platform by clicking on the bar <Expert Advisors> located under the menus. (The green reading button indicates that the platform allows the use of Expert Advisor, and a red cross, it did not allow)

Metatrader 4 Expert Advisors

If the following smiley appear, this means that you have forgotten to allow the live trading for the EA (step 2) :

Metatrader 4 Expert Advisors

END: Once the EA implemented and enabled on your chart, the logic of the EA will be invoked at every movement (tick) on the current chart display. So at every movement conditions of opening and closure order will be verified and the corresponding actions taken if necessary.

It is possible to apply an EA on a lot of parities and different timeframes. You just need to create a new chart and to apply the EA on it.


An Expert Advisor is running on your machine (client side) and not on the server of your broker. This means that if you lose your Internet connection or if you turn off your computer, the EA will not be active anymore but positions are still open. Do not panic! Modern technology created for us the VPS (VIRTUAL PRIVATE SERVER). I invite you to visit our special page dedicated to VPS by returning immediately to the top of this page.

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