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Code a trial algorithm for cTrader Store

A trial version of an algorithm is often needed for algo creators to pursue an effective distribution strategy in cTrader Store. This article explains how to introduce limitations to trial versions of cBots, indicators and plugins at the code level.

Tip

Duplicate your main algorithm to create a trial version, add limitations to it as explained in this guide and then publish a trial in cTrader Store.

Trial limitations

Trial limitations ensure that potential buyers can test the general behaviour, logic, and quality of your algorithm, but cannot fully replicate the functionality of the paid version.

Common limitations in the code of trial algorithms include:

  • Demo-only operations
  • Backtesting-only operations
  • Daily profit cap
  • Hardcoded symbol and period
  • Hardcoded parameters
  • And more

cBots

The code structure of a trial cBot may resemble this:

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    protected override void OnStart()
    {
        // Trial setup checks (account type, symbol, expiry, etc.)
        // Restrictions logic for the trial
        // before or around your normal trading logic.
    }

    protected override void OnBar()
    {
        // Restrictions logic for the trial
        // before or around your normal trading logic.
    }

    private void RunStrategy()
    {
        // Normal trading logic goes here
        // e.g., signal detection, risk management, order placement.
    }
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_start(self):
        # Trial setup checks (account type, symbol, expiry, etc.)
        # Restrictions logic for the trial
        # before or around your normal trading logic.
        pass

    def on_bar(self):
        # Restrictions logic for the trial
        # before or around your normal trading logic.
        pass

    def run_strategy(self):
        # Normal trading logic goes here
        # e.g., signal detection, risk management, order placement.
        pass

Demo only

Allow the trial bot to run only on demo accounts. If a user attaches it to a live account, the cBot stops executing. 

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    protected override void OnStart()
    {
        if (Account.IsLive)
        {
            Print("This trial version can be used only on demo accounts.");
            Stop(); // Stops the cBot for real accounts
            return;
        }

        RunStrategy(); // <<< Actual trading logic
    }

    private void RunStrategy()
    {
        // Normal trading logic goes here
        // e.g., signal detection, risk management, order placement.
    }
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_start(self):
        if api.Account.IsLive:
            print("This trial version can be used only on demo accounts.")
            api.Stop() # Stops the cBot for real accounts
            return

        self.run_strategy() # <<< Actual trading logic

    def run_strategy(self):
        # Normal trading logic goes here
        # e.g., signal detection, risk management, order placement.
        pass

Backtesting only

Allow the cBot to function only during backtests. If a user tries to use the algorithm to trade in real conditions, nothing happens. 

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    protected override void OnStart()
    {
        if (RunningMode == RunningMode.RealTime)
        {
            Print("This trial version can run only in backtesting mode.");
            Stop(); // Stops cBot
            return;
        }
    }

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_start(self):
        if api.RunningMode == RunningMode.RealTime:
            print("This trial version can run only in backtesting mode.")
            api.Stop() # Stops cBot
            return

    # Rest of your cBot logic

Daily profit cap

Program the cBot to stop operating once the daily net profit reaches a set value.

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    private const double MaxDailyProfit = 20.0;

    protected override void OnStart()
    {
        StopIfMaxDailyProfitReached();

        Positions.Closed += _ => StopIfMaxDailyProfitReached();
    }

    private void StopIfMaxDailyProfitReached()
    {
        var todayProfit = History
            .Where(t => t.ClosingTime.Date == Server.Time.Date)
            .Sum(t => t.NetProfit);

        if (todayProfit < MaxDailyProfit)
            return;

        Print("Trial limit reached: daily profit cap.");
        Stop(); // Stops cBot
    }

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    MaxDailyProfit = 20.0

    def on_start(self):
        self.stop_if_max_daily_profit_reached()
        api.Positions.Closed += lambda _: self.stop_if_max_daily_profit_reached()

    def stop_if_max_daily_profit_reached(self):
        todayProfit = [t.NetProfit for t in History if t.ClosingTime.Date == api.Server.Time.Date]

        if todayProfit < self.MaxDailyProfit:
            return

        print("Trial limit reached: daily profit cap.")
        api.Stop(); # Stops cBot

    # Rest of your cBot logic

Hardcoded symbol and period

If a user tries to run the cBot on another symbol or period, nothing happens.

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    private const string ValidSymbolName = "EURUSD";
    private const string ValidTimeFrame = "Hour";

    protected override void OnStart()
    {
        StopIfSymbolOrTimeFrameIsInvalid();
    }

    private void StopIfSymbolOrTimeFrameIsInvalid()
    {
        if (SymbolName == ValidSymbolName && TimeFrame.Name == ValidTimeFrame)
            return;

        Print($"This trial version works only on {ValidSymbolName} {ValidTimeFrame}.");
        Stop(); // Stops cBot
    }

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    ValidSymbolName = "EURUSD"
    ValidTimeFrame = "Hour"

    def on_start(self):
        self.stop_if_symbol_or_time_frame_is_invalid()

    def stop_if_symbol_or_time_frame_is_invalid(self):
        if api.SymbolName == self.ValidSymbolName and api.TimeFrame.Name == self.ValidTimeFrame:
            return

        print(f"This trial version works only on {ValidSymbolName} {ValidTimeFrame}.")
        api.Stop(); # Stops cBot

    # Rest of your cBot logic

Hardcoded parameters

Code the cBot to always use unfavourable internal constants, such as a small volume or lot size. 

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    // In full version, you might have:
    // [Parameter("Volume (lots)", DefaultValue = 0.1)]
    // public double VolumeInLots { get; set; }

    // In trial version, you can omit parameters entirely
    // and always use a fixed volume amount when executing trades:
    private const string TrialVolumeInLots = 0.01

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    # In full version, you might have:
    # [Parameter("Volume (lots)", DefaultValue = 0.1)]
    # public double VolumeInLots { get; set; }
    # In Python algos you have to define parameters
    # in C# file of your algo

    # In trial version, you can omit parameters entirely
    # and always use a fixed volume amount when executing trades:
    TrialVolumeInLots = 0.01

    # Rest of your cBot logic

Limited daily trades

Configure the cBot to stop trading for the rest of the day after a given number of trades. 

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    private const int MaxTradesPerDay = 5;

    protected override void OnBar()
    {
        if (IsMaxDailyTradeReached())
            return; // Skip trading logic if max trade number reached
    }

    private void IsMaxDailyTradeReached()
    {
        var todayTradesCount = History
            .Where(t => t.ClosingTime.Date == Server.Time.Date)
            .Count();

        if (todayTradesCount < MaxTradesPerDay)
            return false;

        Print("Trial limit reached: maximum trades for today.");
        return true;
    }

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    MaxTradesPerDay = 5

    def on_bar(self):
        if self.is_max_daily_trade_reached():
            return # Skip trading logic if max trade number reached

    def is_max_daily_trade_reached(self):
        todayTradesCount = len([t for t in api.History if t.ClosingTime.Date == Server.Time.Date])
        if todayTradesCount < self.MaxTradesPerDay:
            return False

        print(f"Trial limit reached: maximum trades for today.")
        return True

    # Rest of your cBot logic

Time-limited operations

Code the cBot to send a start date linked to the user's cTID when it is started, and configure it to stop functioning after a fixed period. To prevent users from bypassing the trial start configuration, consider using a remote API service or a similar secure solution. 

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    private const int TrialDays = 5;

    protected override void OnStart()
    {
        // Do the same check on other methods like OnTick, OnBar, etc...
        if (Server.Time >= GetTrialStartTime().AddDays(TrialDays))
            OnTrialExpired();
    }

    private DateTime GetTrialStartTime()
    {
        // Add here the logic for getting trial start time from your secure remote service
    }

    private void OnTrialExpired()
    {
        Print("Your trial period has expired. Please purchase the full version.");
        Stop();
    }

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    TrialDays = 5

    def on_start(self):
        # Do the same check on other methods like on_tick, on_bar, etc...
        if api.Server.Time >= self.get_trial_start_time().AddDays(self.TrialDays):
            self.on_trial_expired()

    def get_trial_start_time(self):
        # Add here the logic for getting trial start time from your secure remote service
        pass

    def on_trial_expired(self):
        print("Your trial period has expired. Please purchase the full version.")
        api.Stop()

    # Rest of your cBot logic

Session-based limitation

Allow the cBot to trade in only one session.

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    protected override void OnBar()
    {
        // Do the same check on other methods like OnTick, etc...
        if (!IsValidSession())
            return
    }

    private bool IsValidSession() => MarketSessions.HasFlag(MarketSession.London)

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_bar(self):
        # Do the same check on other methods like on_tick, etc...
        if self.is_valid_session() == False:
            return

    def is_valid_session(self):
        return api.MarketSessions.HasFlag(MarketSession.London)

    # Rest of your cBot logic

Simulated trades only

Code the cBot to log where it would trade and not execute trades.

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[Robot(AccessRights = AccessRights.None)]
public class Test : Robot
{
    protected override void OnBar()
    {
        // Example: simple signal
        var buySignal = Bars.ClosePrices.Last(1) > Bars.OpenPrices.Last(1);

        if (buySignal)
        {
            // In full version, this is where you would execute an order:
            // ExecuteMarketOrder(TradeType.Buy, SymbolName, 10000);

            // In the trial: only log the virtual action
            Print($"[TRIAL] Would open BUY position at {Symbol.Ask}");
        }
    }

    // Rest of your cBot logic
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_bar(self):
        # Example: simple signal
        buySignal = api.Bars.ClosePrices.Last(1) > api.Bars.OpenPrices.Last(1)

        if buySignal:
            # In full version, this is where you would execute an order:
            # api.ExecuteMarketOrder(TradeType.Buy, api.SymbolName, 10000);

            # In the trial: only log the virtual action
            print(f"[TRIAL] Would open BUY position at {api.Symbol.Ask}")

    # Rest of your cBot logic

Indicators

The code structure of a trial indicator may resemble this:

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[Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
public class Test : Indicator
{
    [Output("Result", LineColor = "DodgerBlue")]
    public IndicatorDataSeries Result { get; set; }

    protected override void Initialize()
    {
        // Trial setup checks go here
    }

    public override void Calculate(int index)
    {
        // Trial indicator logic goes here
    }
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def initialize(self):
        # Trial setup checks go here
        pass

    def calculate(self, index):
        # Trial indicator logic goes here
        pass

Reduced functionality

The trial indicator executes a basic calculation, while the full version contains more advanced logic.

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[Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
public class Test : Indicator
{
    [Output("Result", LineColor = "DodgerBlue")]
    public IndicatorDataSeries Result { get; set; }

    protected override void Initialize()
    {
    }

    public override void Calculate(int index)
    {
        // Trial build: simplified logic only
        Result[index] = (Bars.HighPrices[index] + Bars.LowPrices[index]) / 2;

        // Full version might add more lines, buffers, filters, etc.
    }
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def initialize(self):
        pass

    def calculate(self, index):
        # Trial build: simplified logic only
        api.Result[index] = (api.Bars.HighPrices[index] + api.Bars.LowPrices[index]) / 2

        # Full version might add more lines, buffers, filters, etc.

Hardcoded symbol and timeframe

Code the indicator to show outputs only when a certain symbol and timeframe is used.

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[Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
public class Test : Indicator
{
    [Output("Result", LineColor = "DodgerBlue")]
    public IndicatorDataSeries Result { get; set; }

    private const string ValidSymbolName = "EURUSD";
    private const string ValidTimeFrame = "Hour";

    protected override void Initialize()
    {
        if (!IsSymbolAndTimeFrameValid())
        {
            Chart.DrawStaticText("symbolLimit",
                "Trial version supports only EURUSD and GBPUSD.",
                VerticalAlignment.Center,
                HorizontalAlignment.Center,
                Color.Yellow);

            return;
        }
    }

    public override void Calculate(int index)
    {
        if (!IsSymbolAndTimeFrameValid())
            return;

        // Rest of your indicator logic
    }

    private void IsSymbolAndTimeFrameValid()
    {
        return SymbolName == ValidSymbolName && TimeFrame.Name == ValidTimeFrame;
    }
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    ValidSymbolName = "EURUSD"
    ValidTimeFrame = "Hour"

    def initialize(self):
        if self.is_symbol_and_time_frame_valid() == False:
            api.Chart.DrawStaticText("symbolLimit",
                "Trial version supports only EURUSD and GBPUSD.",
                VerticalAlignment.Center,
                HorizontalAlignment.Center,
                Color.Yellow)
            return

    def calculate(self, index):
        if self.is_symbol_and_time_frame_valid() == False:
            return

        # Rest of your indicator logic

    def is_symbol_and_time_frame_valid(self):
        return api.SymbolName == self.ValidSymbolName and api.TimeFrame.Name == self.ValidTimeFrame

Time-limited operations

Code the indicator to stop displaying outputs once it expires and show only a message. 

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[Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
public class Test : Indicator
{
    [Output("Result", LineColor = "DodgerBlue")]
    public IndicatorDataSeries Result { get; set; }

    protected override void Initialize()
    {
    }

    public override void Calculate(int index)
    {
        if (IsTrialExpired())
        {
            Result[index] = double.NaN;
            return;
        }

        // Rest of your indicator logic
    }

    private bool IsTrialExpired()
    {
        // Here you can check if trial is expired or not
        // You have to store trial start time somewhere secure outside
        // user reach and comapre it with Server.Time

        // You can also let user know trial is expired by showing
        // a text message on chart, ex:
        // Chart.DrawStaticText(
        // "trial_expired",
        // "Trial expired. Please purchase the full version.",
        // VerticalAlignment.Center,
        // HorizontalAlignment.Center,
        // Color.Red
        // );
    }
}

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
import math
class Test():
    def initialize(self):
        pass

    def calculate(self, index):
        if self.is_trial_expired():
            api.Result[index] = math.nan
            return

        # Rest of your indicator logic

    def is_trial_expired(self):
        # Here you can check if trial is expired or not
        # You have to store trial start time somewhere secure outside
        # user reach and comapre it with api.Server.Time

        # You can also let user know trial is expired by showing
        # a text message on chart, ex:
        # api.Chart.DrawStaticText(
        # "trial_expired",
        # "Trial expired. Please purchase the full version.",
        # VerticalAlignment.Center,
        # HorizontalAlignment.Center,
        # Color.Red
        # )

Plugins

The code structure of a trial plugin may resemble this:

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[Plugin(AccessRights = AccessRights.None)]
public class Test : Plugin
{
    protected override void OnStart()
    {
        // Trial setup or logic here
    }

    protected override void OnStop()
    {
    }
}      

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_start(self):
        # Trial setup or logic here
        pass

    def on_stop(self, index):
        pass

Reduced functionality

The trial version includes only basic features, while the full version provides everything. 

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[Plugin(AccessRights = AccessRights.None)]
public class Test : Plugin
{
    protected override void OnStart()
    {
        // Basic features
    }

}      

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_start(self):
        # Basic features
        pass

Time-limited operations

Code the plugin to stop functioning once it expires and only show a message. 

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[Plugin(AccessRights = AccessRights.None)]
public class Test : Plugin
{
    protected override void OnStart()
    {
        // Use same check inside your plugin other methods
        if (IsTrialExpired())
            OnTrialExpired();

        // You can also run timer and keep checking trial expiry
        Timer.Start(100)
    }

    protected override void OnTimer()
    {
        if (IsTrialExpired())
            OnTrialExpired();
    }

    private DateTime IsTrialExpired()
    {
        // Here you have to check if user trial period is expired
        // or not, for that you have to store the trial start time
        // somewhere secure outside user access and compare it with
        // Server.Time
    }

    private void OnTrialExpired()
    {
        // Do whatever you want when trial is expired here
        MessageBox.Show("Trial expired");
    }
}      

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import clr
clr.AddReference("cAlgo.API")
# Import cAlgo API types
from cAlgo.API import *
# Import trading wrapper functions
from robot_wrapper import *
class Test():
    def on_start(self):
        # Use same check inside your plugin other methods
        if self.is_trial_expired():
            self.on_trial_expired()

        # You can also run timer and keep checking trial expiry
        Timer.Start(100)

    def on_timer(self, index):
        if self.is_trial_expired():
            self.on_trial_expired()

    def is_trial_expired(self):
        # Here you have to check if user trial period is expired
        # or not, for that you have to store the trial start time
        # somewhere secure outside user access and compare it with
        # Server.Time

    def on_trial_expired(self):
        # Do whatever you want when the trial has expired here
        api.MessageBox.Show("Trial expired")