Hi @fierce-teacher-22952. We have investigated your issue and found two things that could help. First, in your code you’re using qaMode: kDebugMode. According to the docs: “If qaMode is true, random assignment is disabled and only explicitly forced variations are used.” This means that trackingCallback will not be triggered unless the variation was explicitly forced. Second, we had an issue where the hostURL must end with a slash. So you should use: hostURL: ‘https://cdn.growthbook.io/’ for now. We’re planning to fix this behavior soon.

Are you currently in the experiment, and do you have a feature in the experiment?

Because we are testing that with your code and it is calling trackingCallback.

And are you adding in a right way here ? We need to add there Experiment and ExperimentResult

I see that signature changed in package version 3. Which version should I use?

growthBook = await initGrowthbook();
    final experiment = GBExperiment(
      key: 'offer_card_show_only_first_image',
      variations: [false, true],
    );
    showOnlyFirstImage = growthBook!.run(experiment).value;

this way it works. At least it calls callback.

Thank you for helping me!