What Is a Feature Flag? | Vantage
Feature Flag A feature flag (also called a feature toggle) is a software engineering technique that lets you enable or disable a feature at runtime without deploying new code. Feature flags decouple deployment (shipping code) from release (making it available to users).
Why feature flag matters
Feature flags reduce deployment risk. You can deploy code to production behind a flag, test it with internal users, gradually roll it out to a percentage of users, and instantly disable it if something goes wrong. This makes releases safer and more controlled.
How it works
In the codebase, feature behavior is wrapped in a conditional check: if the flag is enabled, show the new feature; if not, show the old behavior. Flag values are managed in a flag management service (LaunchDarkly, Statsig, or custom). The PM or engineer toggles flags without redeploying.
Common mistakes
Not cleaning up old flags (creates technical debt)
Too many flags active at once (hard to reason about system behavior)
Using flags for permanent configuration (flags should be temporary)
Not monitoring flag-dependent code paths
Not having a flag cleanup process
Related terms
How Vantage relates
Vantage generates tickets that include rollout plans with feature flag strategies. When a ticket specifies "deploy behind feature flag, enable for 10% of users, measure conversion, then full rollout," the PM and engineering team have a clear, traceable plan for safe release.