Feature Flag

Feature flags (also called feature toggles) decouple deployment from release by wrapping new functionality in conditional checks that can be toggled on or off at runtime. This enables progressive rollouts (releasing to 5% of users before going to 100%), instant kill switches for broken features, A/B testing, and per-customer feature gating. Tools like LaunchDarkly, Unleash, and Statsig provide managed feature flag infrastructure. Feature flags are essential for safe continuous deployment — they transform risky big-bang releases into controlled, reversible rollouts. Most vibecoded applications deploy features all-or-nothing with no way to roll back without a full redeploy.