What is Feature Flag?
A feature flag (or feature toggle) is a mechanism that lets teams turn functionality on or off in production without deploying new code. It decouples releasing a feature from deploying it, enabling gradual rollouts, targeted access, experimentation and instant rollback if something goes wrong.
Reviewed by Gensudo Team · 23 July 2026
In more depth
Feature flags wrap code paths in conditional switches controlled at runtime, so a feature can be merged and deployed while hidden, then enabled for specific users, percentages or environments. They underpin practices such as canary releases, A/B tests, beta programmes and kill switches. The trade-off is added complexity: stale flags accumulate as technical debt and must be cleaned up once a feature is fully rolled out.
Why it matters
Coupling release to deployment makes shipping risky and slow, forcing big-bang launches that are hard to undo. Feature flags let teams deploy continuously but release deliberately, limit the blast radius of a bad change by rolling out gradually, and recover instantly by flipping a switch rather than rushing a fix, which makes frequent delivery far safer.
A product example
A team launches a new pricing page behind a flag, enabling it first for internal staff, then 5% of traffic while watching metrics. When conversion holds, they ramp to 100%; when an earlier feature misbehaved, they had disabled it in seconds without a redeploy.
Documents where this shows up
Product Launch Checklist for Product Managers · Validation Findings Report for Product Managers
Related terms
A/B Testing · Minimum Viable Product (MVP) · Technical Debt · Definition of Done