Feature Flag Rot
ELI5 — The Vibe Check
Feature flag rot is when a flag has been sitting around for so long that nobody knows what it does or what breaks when you flip it. The team that wrote it is gone. The docs are gone. The flag stays.
Real Talk
Feature flag rot is the degradation of a flag's documentation, ownership, and behavioral clarity over time. Rotted flags can't be safely removed (unknown blast radius) or safely toggled (unknown behavior). They're a specific failure mode of poor toggle hygiene, especially in long-lived services with staff turnover.
When You'll Hear This
"That flag has been there since 2023 — total feature flag rot." / "Ownership audit this quarter to catch feature flag rot."
Related Terms
Documentation
Documentation is written explanation of how your code works and why.
Feature Flag
A feature flag is a toggle that lets you turn features on or off without deploying new code.
Toggle Debt
Toggle debt is the pile of unused feature flags slowly suffocating your codebase. Every 'if (flag)' branch is cognitive load.
Toggle Hygiene
Toggle hygiene is the practice of cleaning up feature flags after they've served their purpose.