Feature Flags — Targeting, Experimentation & Kill Switches

DevOps

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• Feature Flags — Targeting, Experimentation & Kill Switches

  6 studies
  1. 1.Feature Flags — Targeting, Experimentation & Kill SwitchesFeature flags (feature toggles) decouple deploy from release: you ship dark code safely, then turn behavior on for segments, percentages, or experiments, and turn it off instantly when metrics or incidents demand it. This hub teaches release, experiment, ops, and permission toggles, sticky bucketing, targeting, A/B guardrails, progressive delivery, kill switches, and hygiene so flags do not become permanent debt.
  2. 2.Flag Types & Evaluation — Boolean, Multivariate, Percentage & Sticky BucketsFlag types and evaluation mechanics decide whether your rollout is trustworthy. Booleans gate on or off. Multivariate flags return named variants. Percentage rollouts need a sticky hash so the same subject stays in the same bucket. This lesson implements those sketches, contrasts hash choices, and shows why a fresh random draw breaks experiments and UX.
  3. 3.Targeting & Context — Attributes, Segments, Rules & PrecedenceTargeting answers who gets a variant: attributes on the evaluation context, reusable segments, and ordered rules with a clear precedence. Bad targeting causes support chaos and biased experiments. This lesson shows a minimal rules engine, how segments are composed, and how exposure differs from authorization.
  4. 4.Experimentation & A/B — Exposure, Metrics, Guardrails & PeekingAn experiment is a sticky multivariate flag plus exposure logging, a success metric, and guardrail metrics, run with statistical discipline. This lesson covers assignment versus exposure, sample ratio mismatch, peeking, a one-sentence view of CUPED, and when a dedicated experiment platform earns its place next to the flag.
  5. 5.Progressive Delivery & Kill Switches — Canary, Ramp, Instant RollbackProgressive delivery ramps a feature to a larger audience only while metrics stay healthy. A kill switch forces the safe path the moment they do not. This lesson contrasts flag ramps with Kubernetes traffic canaries, designs soak times and abort gates, and defines who may flip a kill switch and how wide the blast radius is.
  6. 6.Flag Architecture & Hygiene — SDK Placement, Consistency, Stale Flags & DebtFlags fail quietly when the architecture is wrong, and loudly when hygiene is ignored. This lesson places SDKs so services do not split-brain a decision, adopts an OpenFeature-style seam, and sets a lifecycle from create to ramp to delete so stale flags do not become a permanent settings database.