What Are Feature Flags in Production?
Feature flags in production are a technique that lets teams turn features on or off in a live system without redeploying code.
When to Use
Use them for safe rollouts, A/B testing, or quick rollbacks. They’re common in gradual deployments, canary releases, and as kill switches when something breaks.
Example
An e-commerce site enables a new checkout page for 5% of users via a feature flag and turns it off instantly if bugs appear.
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Why Is It Important
Feature flags decouple deployment from release, enabling faster feedback, safer experimentation, and immediate rollback if issues arise.
Interview Tips
In interviews, define them clearly, explain benefits, and give a simple example. Highlight risks like “flag debt” if old flags are not removed.
Trade-offs
They improve flexibility and safety but increase code complexity and require careful flag management.
Pitfalls
Common mistakes include leaving unused flags, overusing them instead of testing, and poor documentation that confuses teams.
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