Lld
Low-Level Design
Easy
Zenith Feature Flag SDK
Design a client-side SDK for a Feature Flag service. The SDK should allow developers to check if a feature is enabled for a specific user (e.g., `if (sdk.isEnabled('new_ui', userContext))`). Requirements: 1) Support local overrides for testing, 2) Support percentage-based rollouts (e.g., 10% of users), 3) Cache flag configurations locally and update them periodically via a background sync, and 4) Provide a fallback value if the service is unreachable.
Key concepts
observer patternsingletonstrategy pattern
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