Feature Flag Service
ELI5 — The Vibe Check
Feature flags are like light switches for your code. You deploy new features turned OFF, then flip the switch for 1% of users, then 10%, then everyone. If something breaks, just flip it off — no redeploy needed. It's deploying code like a cautious cook who adds spice gradually instead of dumping the whole jar.
Real Talk
A service that enables runtime toggling of application features without code deployments. Feature flag services (LaunchDarkly, Unleash, Flagsmith) provide SDKs for evaluating flags per-user, percentage rollouts, A/B testing integration, and audit logs for compliance.
When You'll Hear This
"We deploy behind feature flags — the code is in production but invisible until we flip the flag." / "Feature flags let us kill a broken feature in 30 seconds instead of waiting for a rollback deploy."
Related Terms
A/B Testing
Show half your users a blue button and the other half a green button, then see which one gets more clicks. That's A/B testing — science experiments on your
Canary Analysis
Named after canaries in coal mines — you send a small version of your new deployment into production first to see if it dies. Route 5% of traffic to the ne
Trunk-Based Development
Instead of giant feature branches that live for 3 weeks and cause merge hell, trunk-based development has everyone commit to main every day.