Make code deployments completely safe and change your application in production in real time with LaunchDarkly using percentage-based rollouts, kill switches, and A/B and multi-variant testing Key FeaturesLearn how to work with LaunchDarkly to turn features on and off within your production applicationsExplore the ways in which feature management can change how software is built and how teams workMaster every aspect of LaunchDarkly's functionality to test in production and learn from your usersBook Description Over the past few years, DevOps has become the de facto approach for designing, building, and delivering software. Feature management is now extending the DevOps methodology to allow applications to change on demand and run experiments to validate the success of new features. 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 and configuring simple feature flags to turn features on and off, you'll learn how simple functionality can be applied in more powerful ways with percentage-based rollouts, experimentation, and switches. You'll see how feature management can change the way teams work and how large projects, including migrations, are planned. Finally, you'll 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'll have gained a comprehensive understanding of LaunchDarkly, along with knowledge of the adoption of trunk-based development workflows and methods, multi-variant testing, and managing infrastructure changes and migrations. What you will learnGet to grips with the basics of LaunchDarkly and feature flagsRoll out a feature to a percentage or group of usersFind out how to experiment with multi-variant and A/B testingDiscover how to adopt a trunk-based development workflowExplore methods to manage infrastructure changes and migrationsGain an in-depth understanding of all aspects of the LaunchDarkly toolWho this book is for This book is for developers, quality assurance engineers and DevOps engineers. This includes individuals who want to decouple the deployment of code from the release of a feature, run experiments in production, or understand how to change processes to build and deploy software. Software engineers will also benefit from learning how feature management can be used to improve products and processes. A basic understanding of software is all that you need to get started with this book as it covers the basics before moving on to more advanced topics.