Feature Flag Management

Feature flags separate deployment from release. They are powerful safety controls when owned and retired; they become production debt when left unmanaged.

Flag types

• Release flags control gradual exposure of new functionality.
• Experiment flags test product hypotheses.
• Operational flags disable risky or expensive behavior quickly.
• Permission flags expose features to entitled users or tenants.
• Migration flags shift traffic or behavior during system changes.

Flag metadata

Every flag should include:

• Owner.
• Purpose.
• Creation date.
• Expected removal date.
• Default state.
• Targeting rules.
• Impact if toggled.
• Link to rollout or migration plan.

Lifecycle

Practices

• Keep defaults safe for new environments.
• Log or audit production flag changes.
• Test both enabled and disabled paths while the flag exists.
• Remove flags after rollout or migration completes.
• Use server-side enforcement for authorization-sensitive behavior.

Watchouts

• Nested flags make behavior hard to reason about.
• Stale flags create dead code and hidden risk.
• Client-side flags can leak upcoming features or sensitive logic.
• Emergency flags must be documented in runbooks.