Preface

Over the past few years, DevOps has become the de facto approach for designing, building, and delivering software, but feature management is now extending this methodology. From feature toggles to experimentation, from rollouts to migrations, if you want to make feature management happen, LaunchDarkly is the tool for you.

This book explains how feature management is key to building modern software systems. Starting with the basics of LaunchDarkly, you will learn how the simple feature flag can be used to turn features on and off. Then you will discover percentage- and ring-based rollouts, how to gain insights from your customers via experiments, and how switches can help maintain a good production environment. You will see how feature management can change the way teams work and how large projects, including migrations, are successfully achieved.

Finally, you will discover various uses of every part of the tool to gain mastery of LaunchDarkly. This includes tips and tricks for experimentation, identifying groups and segments of users, and investigating and debugging issues with specific users and feature flag evaluations. By the end of the book, you will have gained a comprehensive understanding of LaunchDarkly, along with knowledge of the adoption of trunk-based development workflows, multi-variant testing, and managing infrastructure changes and migrations.