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Using feature flags is pretty much the standard when rolling out new features. That’s why choosing a development strategy that revolves around this technique is a great way of making sure feature releases have the result you’re expecting.
We’re talking about feature flag-driven development.
In this primer, we’ll discuss why feature flag-driven development is such a great strategy and how it can have a real impact both on your user’s customer experience and your revenue numbers.
We’ll go over:
Let’s begin with a quick definition.
Feature flag-driven development is a software development technique where new features are wrapped in conditional code blocks called feature flags. These flags act like switches, allowing developers to turn features on or off without needing to redeploy the entire application.
This approach gives teams immense control over how and when features are released. They can roll out features gradually to subsets of users, minimizing risk and gathering real-world feedback before a full launch.
For example, a new recommendation engine could be enabled for a small percentage of users to gauge its effectiveness before making it available to everyone.
Additionally, feature flags allow for real-time adjustments. Developers can quickly disable features if issues arise or tailor the user experience based on specific criteria. Imagine having the ability to instantly activate a promotional banner for a special sale, but only for users in a specific region. Feature flags make this kind of dynamic control possible.
To fully grasp how feature flag-driven development works, let's dive into the three key building blocks:
At their most basic level, feature flags are simple "true" or "false" (boolean) toggles built into your code. They work like this:
This simple concept gives you the power to decide when and how features become visible.
While you could technically manage feature flags with basic code, dedicated flag management systems make the process much more powerful. These platforms offer:
Results start to become more evident when feature flags are woven into your continuous integration and continuous deployment (CI/CD) processes. Here's how it works:
Feature flags transform the way software is built and released. Here are some of the most significant advantages:
Instead of releasing a whole new feature to everyone at once, flags let you roll it out gradually. Start with a small percentage of users, monitor how things go, and collect feedback. If everything looks good, slowly expand the rollout. This approach helps you:
We all know the fear of a big release going bad. Feature flags can act as emergency "off" switches. Did you discover a critical bug in your fancy new feature? Disable its flag instantly, and the problem goes away for your users. No frantic code rollback, no all-hands-on-deck panic.
This means you can:
Apart from letting you turn features on and off, having a feature flag-driven development strategy makes it easy to try different variations through A/B testing. This means that with a feature flag system, you can:
The shift to feature flag-driven development requires some adjustments to your process, a little planning, and the right tools. Let's break down the key steps required to successfully integrate this methodology into your workflow.
Getting started with feature flags involves some key choices and integrating them directly into your codebase. Here's how to approach this:
Feature flags become truly powerful when they're baked into your continuous integration and continuous development processes. Consider these factors:
Treating feature flags with care throughout their entire lifecycle prevents headaches and maximizes their benefits. Here's what to keep in mind:
Choosing clear and descriptive names for your flags is more important than it might seem initially. A good naming system makes it a breeze to understand what each flag controls, its current status, and even who created it. Consider a structure like this:
Example: new_search_testing_20240509
This kind of structure makes managing a large number of flags much simpler.
Feature flags aren't just about release control — they also help you understand how your changes really affect users. Make sure you have monitoring in place to track key metrics when a flag is active. Here's what to watch for:
By monitoring metrics like conversion rates, completion times, or user satisfaction scores, you can identify the variation that delivers the best results for your target audience.
Feature flags touch many aspects of the development and release process. Smooth communication is crucial to prevent surprises and misunderstandings. Make sure the following people are kept informed:
It's easy to get excited about using feature flags to control releases. However, just like any code, feature flags can become a problem if not managed carefully. Leaving outdated flags in your codebase long after a feature is public is a recipe for technical debt.
This extra layer of conditional logic makes your codebase harder to understand and maintain over time. Additionally, old flags might unexpectedly interact with new code, leading to bugs that are difficult to track down.
To prevent this, make regular audits of your flags a part of your process. Remove flags for fully released features and set policies on how long a flag should remain active even after the feature is no longer under development.
Feature flags introduce a new layer of complexity into your system. As their use grows, testing becomes more involved, since you need to test various combinations of flags being active and inactive to ensure everything works as intended.
Additionally, keeping track of what each flag does, who owns it, and its intended lifespan can be tricky, especially in larger teams.
To manage this complexity, thorough documentation of each flag's purpose is crucial. Using a centralized feature flag management system can help visualize and organize all your flags.
Lastly, consider implementing a global "kill switch" as a safety net. This would allow you to instantly disable all feature flags if a major issue arises, minimizing potential damage and giving your team time to troubleshoot effectively.
You should now understand how feature flags give you control over releases, enable experimentation, and let you tailor user experiences.
Eppo is a powerful experimentation and feature management platform that takes feature flagging to the next level, empowering you to unlock the full potential of feature flag-driven development.
Other feature flagging tools can leave room for uncertainty when it comes to A/B testing and analyzing results. Eppo prioritizes statistical rigor, delivering clarity and transparency throughout the entire process.
What’s more, Eppo integrates effortlessly with your existing data warehouses (Databrick, Redshift, BigQuery, Snowflake, and more).
This means data is being pulled from your internal source of truth. This minimizes setup time, letting you start experimenting immediately and seeing results sooner.
Here’s how Eppo aids you in your feature flag-driven development strategy:
Learn about feature flag-driven development, its benefits, implementation, and best practices. See how Eppo simplifies feature management for data-driven releases.