Feature Flags: The stupid simple way to de-stress production releases

Feature flags (or feature toggles) are a technique for incrementally rolling out functionality in an application. Work that is not completely ready to go live can be released in chunks while being hidden by a flag. These flags are usually configured per-environment so that you can, for instance, enable a feature on a staging site before turning it on in production.Feature Toggles by Martin Fowler is the canonical article on this practice and outlines a full taxonomy of feature toggles.