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How to run an AB Test in Python

Running a simple A/B experiment in a web page with Python and the Statsig SDK involves a few distinct steps, including creating a basic web server, integrating with Statsig for A/B testing, and configuring the experiment via the Statsig console. Below is a step-by-step guide.

Step 1: Create a Basic Python Web Server

First, you'll need a simple Python web server. Flask is a lightweight WSGI web application framework that's perfect for this purpose.

Step 1: Creating a Simple Python "Hello World" Application

  1. Set Up Your Python Environment:

    • Ensure Python is installed on your system. You can download it from
    • Optionally, create a virtual environment for your project to manage dependencies:
      python -m venv venv
      source venv/bin/activate # On Windows use `venv\Scripts\activate`
  2. Create a New Python File:

    • In your project directory, create a file named
  3. Write a Simple Python Program:

    • Open in your favorite text editor or IDE and write a simple Python program:
      print("Hello, World!")
  4. Run Your Program:

    • Run your program from the command line or terminal:
    • You should see "Hello, World!" printed to the console.

Step 2: Integrate Statsig for A/B Testing

  1. Install Statsig SDK:

    • Add the Statsig SDK to your project:
      pip install statsig
  2. Initialize Statsig in Your Application:

    • Modify to include initialization of the Statsig SDK and to check a feature flag. You will need a server secret key from Statsig, which you can get from the Statsig dashboard.

      from statsig import statsig
      from statsig.statsig_user import StatsigUser

      # Initialize Statsig with your server secret key
      user = StatsigUser(
      user_id = "user123",
      email = "",
      ) # Customize user info as needed
      experiment = statsig.get_experiment(user, 'your_experiment_name')
      text_to_show = experiment.get('text', 'Hello, World!')

      # Shutdown Statsig before your application exits
    • Replace 'your_server_secret_key' with your actual server secret key from Statsig.

    • Replace 'your_experiment_name' with the name of your experiment.

Step 3: Creating the A/B Test in Statsig Console

  1. Log Into Statsig Console:

    • Access the Statsig Console and sign in.
  2. Create an Experiment:

    • Navigate to the "Experiments" section and click "Create New".
    • Fill in the experiment details, including a unique key for 'your_experiment_name'.
  3. Configure Experiment Variants:

    • Define your variants, for example, variant_a and variant_b.
    • Add a parameter called 'text' for each variant and configure the text you wish to display, such as "This is Control Variant" and "This is Test Variant".


  4. Launch Your Experiment:

    • After setting up your variants and their parameters, save your configurations and start the experiment.

By following these steps, you've set up a Python Flask application that utilizes Statsig for running an A/B test, dynamically serving different text content based on the experiment's variant. This setup enables data-driven decisions and iterative improvements based on user interactions.