What is Sunset Protocol?

The Sunset Protocol is a structured deprecation methodology introduced by Richard Ewing in Built In for safely removing features from a software product. It provides a governance framework for subtraction — the organizational discipline of removing things, which is harder politically than adding them.

The Sunset Protocol has five stages:

Stage 1: Identify — Flag features below 5% of peak usage, $0 revenue attribution, or maintenance cost exceeding 10% of value contribution.

Stage 2: Quantify — Calculate total cost of keeping the feature alive: direct maintenance hours × fully-loaded engineer cost × opportunity cost multiplier.

Stage 3: Communicate — Notify affected users and stakeholders with clear timelines. Provide migration paths where applicable.

Stage 4: Deprecate — Feature flag the feature off for new users, then gradually for existing users. Monitor for unexpected breakage.

Stage 5: Remove — Delete the code with rollback capability. Clean up dependencies, tests, and infrastructure. Monitor for 30 days post-removal.

The Sunset Protocol is the execution methodology that pairs with the Kill Switch Protocol (which identifies what to kill) and Feature Bloat Calculus (which quantifies why to kill it).