Suggest an editImprove this articleRefine the answer for “How do feature flags help test new features?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Feature flags** let teams test new features live but safely, because they can be turned on selectively - for a subset of users, environments, or even specific devices - without shipping a new version. **Key point:** if something breaks, the feature can be turned off instantly, without rolling back code or a release.Shown above the full answer for quick recall.Answer (EN)Image**Feature flags** let teams test new features **live but safely**, because they can be turned on selectively - for a subset of users, environments, or even specific devices - **without shipping a new version**. --- ### How it works 1. **The new feature is added to the code**, but "hidden" behind a flag. While the flag is off, users do not see it. 2. **The team turns the feature on only for a test audience** - for example, QA, internal staff, or 5% of real users. 3. **Data and feedback are collected:** user behavior, errors, load speed, conversion. 4. **Gradual rollout:** if everything is stable, the flag is turned on for 20%, then 50%, then everyone. 5. **If something breaks, the feature is turned off instantly**, without rolling back code or a release. --- ### Benefits for testing - **Safety:** you can test "in production" without risking the whole system. - **A/B testing:** different users see different versions, and the team evaluates which is better. - **Flexibility:** QA, developers, and analysts can control feature rollout without involving DevOps. - **Fast feedback:** there is no need to wait for the next release to see the result of a change. --- ### Conclusion **Feature flags** make testing new features **controllable and reversible**. They allow hypotheses and user behavior to be checked **in production, but without risk**, turning the release process into a safe experiment.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.