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# A pocket guide to Feature Flags

Canonical URL: https://posthog.com/learn/feature-flags/pocket-guide

A [feature flag](https://posthog.com/docs/feature-flags.md) separates deploying code from releasing it. You merge the change turned off, then decide from PostHog who gets it: your team first, then 5% of users, then everyone. If errors climb at 5%, you flip the flag off without needing a revert.

This guide follows one flag, `new-checkout`, through its whole life: checked in code, rolled out a few people at a time, switched off when something breaks, tuned with a payload, tested as an experiment, and removed once it has done its job.

[Pocket guide to: Feature Flags](https://posthog.com/learn/feature-flags/pocket-guide/101.md)