Feature flags (also known as feature toggles) are a technique in software development that allows developers to enable or disable specific features or functionality at runtime without deploying new code. Essentially, they act as switches that control whether a feature is active in a given environment, such as production, staging, or testing.

Throughout this book, we explore the power of feature flags in modern software development. From enabling safer deployments and rapid experimentation to managing complex release workflows, feature flags have become an indispensable tool for teams striving for agility, stability, and innovation.