Feature Flags Kill Switch in a Node.js Backend: Safe Rollout and Fallback Defaults

In a Node.js backend, feature flags and kill switches must utilize bounded timeouts, cached decisions, and safe fallback defaults to prevent evaluator outages from corrupting experiments. For media and fintech rollouts, flag decisions should be local and observable, ensuring that network stalls do not create uncertainty. Architecture should favor signal quality over noisy client-side evaluations, employing local shutdown controls that fail closed and separate monitoring systems to record transitions and consequential denials during incidents.