A practical guide for solo developers and small teams on when and how to use feature flags without over-engineering. Covers four types of flags (release toggles, kill switches, gradual rollouts, experiments), when to skip flags entirely, and three progressive setups: a config file constant, a database table with percentage bucketing, and hosted services like ConfigCat, Flagsmith, Statsig, or Unleash. Includes concrete TypeScript code for a database-backed flag system with stable user bucketing, a provider-agnostic wrapper for easy migration, flag hygiene practices with sunset dates, a step-by-step rollout pattern, and common mistakes to avoid. The author's production setup uses a Postgres table with an admin UI and no third-party service, adding Statsig only for A/B testing.
Table of contents
What Feature Flags Actually DoWhen You Do Not Need A FlagWhen You Actually Need A FlagThe Three Setups That Cover Solo And Small-Team ScaleThe Wrapper That Makes Migration EasyThe Hygiene That Keeps Flag Sprawl In CheckThe Pattern For Rolling Out Without PainCommon Mistakes That HurtThe Honest Cost PictureWhat I Run In ProductionWhat I Would Tell You If You AskedSort: