Feature Flag Best Practices

by Pete Hodgson

Whether you want to fine-tune operational control or conduct A/B/n tests, feature flags make it easy to deliver software features quickly and safely. With this practical book, developers will learn eight best practices for using feature flags in production, including how to configure and manage a growing set of feature flags within your product, maintain them over time, manage infrastructure migrations, and more.

Pete Hodgson and Patricio Echagüe from Split demonstrate how feature flags help modern product delivery teams reduce risk by decoupling code deployment from feature release. You’ll learn how to maintain flag consistency in different scenarios and how to develop, test, and work with feature flags at scale.

With these practices, you will:

Make sure users in a test still have access once a feature is ramped up
Learn flag strategies for transitioning users from “anonymous” to “logged in”
Keep flagging decisions on the server to maintain performance and security
Use patterns to make incremental, backward-compatible database changes
Implement flagging decisions as close to business logic as possible
Have each flag owned by one team responsible for rollout and monitoring
Consider testability when using feature flags in combination with CI practices
Maintain a process for identifying and tracking flags
Examine the effect a feature flag is having on your business

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Reviews

[Guillermo · Rating 5 out of 5]

An excellent primer on feature flags, quick and comprehensive, also a little of an ad for Split, a product solving the many problems feature flag users face.

[Elizabeth · Rating 4 out of 5]

Good intro to feature flags and best practices. A little fuzzy on the implementation details, which would rely heavily on the feature flag provider. So, chicken-and-egg scenario there.