Track · 2:30 · Liner note
First a Few, Then Everyone
A feature flag is a runtime switch that lets a team release a change to a few users first, widen exposure gradually and turn it off without redeploying.
Ship the code dark, turn it on for a few users, watch, then widen. A feature flag separates deploying a change from releasing it, so exposure becomes a dial instead of a cliff. First a Few, Then Everyone is that rollout order, and its best feature is the off switch, which works without a new deploy.
Decide in advance what you will watch and which result reverses the rollout. Clean up flags after launch, or the code fills with dead branches that nobody dares delete.