Maintaining Fallback Values

Fallback values can become stale as flags evolve. Use these methods to ensure fallback values remain accurate and up-to-date.

Create a Formal Process

Establish a formal process for defining and updating fallback values:

Process steps:

1. Define fallback values at flag creation - Require fallback values when creating flags
2. Document fallback strategy - Document why each fallback value was chosen (failing closed vs. failing open)
3. Review fallback values during flag lifecycle - Review fallback values when:
   • Flags are promoted from development to production
   • Flags are modified or targeting rules change
   • Flags are deprecated or removed
4. Update fallback values as flags mature - Update fallback values when flags become GA or stable
5. Test fallback values - Include fallback value testing in your testing strategy

Documentation template:

Flag: new-checkout-flow
Fallback value: false - failing closed
Rationale: New feature not yet validated in production. Safer to use legacy checkout during outages.
Review date: 2024-01-15
Next review: When flag reaches 50% rollout