Feature rollouts
Ship to 10% first. If it breaks, kill it. If it works, ramp it.
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Feature Flags are how you avoid betting 100% of your users on that 80% confidence.A new flag has three knobs that, used together, turn a risky deploy into a controlled rollout:
- Rollout percentage. Start at 10%. If nothing breaks, raise to 25%, then 50%, then 100% over a few days. 10% isn’t conservative, it’s the minimum viable sample. Skipping the ramp because you’re confident is how a bad Tuesday becomes a bad Wednesday.
- Segment targeting. Roll out to your “beta-tester” segment first, or to “users on the free plan” so the change can’t break anyone paying you. Multiple criteria can stack.
- Kill switch. If anything looks bad, flip the flag off. The change disappears from everyone instantly. No deploy. No rollback. No 2am git revert.
Most rollouts that go well start as “5% in prod, 100% in the beta-testers segment, kill switch ready, watching the error log.” Most rollouts that go badly start as “100% in prod, deploying on a Friday, what could go wrong.”
Once the change has been at 100% for a week and nothing has caught fire, remove the flag. Dead flags pile up faster than you think.