Do I need a vendor, or can I self-host?

Both work. If you have strict data boundaries or want zero SaaS runtime dependency, run Unleash/Flipt behind a proxy. If you need speed-to-value, LaunchDarkly with Terraform control is solid. Use OpenFeature either way to keep your app code vendor-neutral.

How do I prevent a flag provider outage from taking me down?

Local evaluation with cached configs, short timeouts, and safe defaults. Add a service-level kill switch (env/ConfigMap) and an ingress-based header override. Treat the provider as optional, never on the hot path.

Aren’t canaries enough? Why flags too?

Canaries protect deploy risk; flags protect release risk and allow targeting by cohort, geography, or account. Use both: Argo Rollouts/Spinnaker for canary deployments and feature flags for behavior gating.

What about performance overhead in hot paths?

Use SDKs with in-memory caches and evaluate once per request/session. Avoid per-call network fetches. Pre-warm caches and measure tail latency impact; it should be sub-millisecond.

How do I handle database migrations safely with flags?

Use double-write → read-switch → cleanup. Validate parity with jobs, not anecdotes. Keep the path reversible until you’ve proved parity over time windows under real load.

Release-engineering · Dec 5, 2025 · 10 minute read

The Feature Flag System That Cut Our MTTR to Minutes (Without Torching CFR)

Feature flags aren’t magic. Design them like safety gear, measure them like an SRE, and wire them like infra—then you can ship risky changes safely, fast.

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The Feature Flag System That Cut Our MTTR to Minutes (Without Torching CFR)

Key takeaways

Implementation checklist