Feature flags are powerful tools that enable teams to deploy code safely and control feature releases. Implementing them effectively requires following established best practices to avoid potential pitfalls.
Feature flag best practices include using clear naming conventions, implementing proper access controls, setting up automated testing, planning for flag removal, documenting flag purpose and usage, and monitoring flag performance impact.
Temporary feature flags used for rollouts or experiments should be removed once they've served their purpose, typically within 30-90 days. Permanent flags for system configuration may remain indefinitely, but should be regularly reviewed.
Feature flag technical debt occurs when temporary flags remain in your codebase longer than needed, increasing complexity and maintenance burden. To avoid this, implement a systematic review process, flag expiration dates, and automated cleanup procedures.
Use a consistent naming convention that includes the flag purpose, affected feature, and context. For example: 'enable_new_checkout_flow' or 'release_user_profile_v2'. This makes flags easier to understand and manage at scale.
Yes, poorly implemented feature flags can impact performance, especially with high-volume client-side evaluations. Minimize performance impact by caching flag values, using efficient evaluation logic, and avoiding excessive flag checks in critical paths.
For microservices, consider using a centralized feature flag service that all services can query, implementing consistent evaluation logic across services, and designing flags that work within service boundaries while maintaining system-wide consistency.