Getting Started with Feature Management & Experimentation (FME)

Overview

VWO Fullstack has evolved into VWO Feature Management & Experimentation (FME), offering several new capabilities. FME is a one-stop solution for managing features, executing progressive rollouts and automating guarded releases, running A/B tests, and delivering personalized experiences.

It helps understand feature impact, accelerate shipping velocity, and ensure deployment safety—an approach trusted by the best tech-driven companies.

FME supports multiple SDKs and frameworks across digital platforms, such as web, mobile, tablet, and kiosks, catering to different development environments. The complete list and their specific implementations are here.

What's New in VWO FME (for existing VWO Fullstack users)?

The following table includes a list of all capabilities that VWO FME offers:

Key Concepts in VWO FME

This infographic illustrates the end-to-end workflow of using VWO FME—from flag creation to analyzing the impact through detailed reports.

This section further explains each key concept in detail.

Feature Flags

Feature flags enable you to control when and how new features are shown to users, independent of your deployment cycles.

Each feature flag includes a default or control variable. You can define multiple variables per flag.

Variables can be set to different types—Text, Number, Boolean, or JSON (especially useful for dynamic, complex configurations).

This flexibility allows you to manage various scenarios, from simple feature toggles to intricate logic adjustments using VWO.

Variables

Variables help you define customizable elements within your feature flags—like UI components, algorithms, AI models, or specific logic paths—without redeploying your application.

You can modify these components instantly through the VWO platform by setting them as variables. This helps you respond rapidly to user feedback, adjust configurations, and iterate quickly on features.

Variations

Variations allow you to assign values to your defined variables. Different variable values show different variations of a feature.

By comparing how users engage with each variation, you can clearly identify which option performs best. This will help your team make data-informed decisions and optimize feature performance.

Metrics

Metrics let you measure the real-world impact and effectiveness of your feature releases or experiments, helping you see what’s working.

They’re calculated directly from events triggered by user actions in your app or website. For example, when a user views a page or clicks a button, each action is recorded as an event.

Metrics aggregate these individual events into meaningful data—like total page views, button click counts, or conversion rates—giving your team clear insights into feature performance.

Rules

Rules let you control precisely who experiences a feature, participates in an experiment, or receives personalized content.

You can target users based on attributes (e.g., location), behaviors (actions users have or haven’t taken), or even roll out features to a defined percentage of your audience within a specified time frame.

• Rollout Rule: Gradually expose new features to controlled groups of users, minimizing risk while allowing your team to monitor performance carefully before a broader release.
• Testing Rule: Easily conduct A/B tests, delivering different feature variations to your users. Quickly determine the variation that achieves your desired outcomes by comparing performance metrics.
• Personalize Rule: Give customized experiences tailored specifically for certain user segments, ensuring your content or features resonate more deeply and drive stronger user engagement.

Step-by-Step Guide to Getting Started

Before starting these steps, make sure you have an active VWO account. If not, you can sign up for a 30-day free trial.

Follow this guide to set up VWO’s FME efficiently, empowering your team to manage features confidently, run tests, personalize experiences, and streamline rollouts.

Step 1: Set up your feature flag

• Create Feature Flag: On the VWO dashboard, navigate to Feature Management and create your new feature flag.
• Define Variables: Decide what aspects of your feature you want dynamic (e.g., UI text, button colors, algorithms) and specify their data types (Boolean, text, number, JSON).
• Create Variations: Set up multiple variations with different variable values to effectively test or personalize your feature.

Step 2: Define metrics

Identify and configure metrics (e.g., clicks, conversions, response time, error rates) to measure your feature's performance and success.

Step 3: Establish rules

Choose and create rules according to your rollout strategy:

• Rollout Rule: For progressive rollout to a limited audience (e.g, 10% of users)
• Testing Rule: To run controlled experiments with variations (e.g, test pricing variations)
• Personalize Rule: Customize features specifically tailored for user cohorts (e.g, personalize UX for premium users)

Step 4: Integrate SDK and implement code

This infographic illustrates how VWO dynamically evaluates feature flags at runtime to deliver the appropriate user experience based on flag status.

To integrate the SDK and implement the code:

1. Integrate the relevant VWO SDK into your codebase. Here is the complete list.
2. Initialize the SDK using the init() function near your app’s existing setup code.
   • Set up a polling interval or implement a webhook to ensure the SDK always receives the latest changes.
3. Before your new feature’s code, call the getFlag() function, passing user information through the userContext object. This checks if the feature is active for this specific user.
   • If the feature flag is active for the user, execute the new feature’s code block. Use getVariable() to fetch different configurations tied to the feature. The variable values depend on the feature flag rules and the variation assigned to the user based on those rules.
   • If the feature flag isn’t active, execute the original code block without the new feature.

For more information about the implementation, refer to our SDK documentation.

Practical Use Cases

Example 1: AI model testing

Example 2: Search algorithm optimization

Example 3: Improve user onboarding flow

Need more help?

For further assistance or more information, contact VWO Support.