#Feature Flags
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Statsig Under the Hood: A Deep Dive into Internal Architecture and Implementation
21 min read • Published on • Last Updated OnStatsig is a unified experimentation platform that combines feature flags, A/B testing, and product analytics into a single, cohesive system. This post explores the internal architecture, SDK integration patterns, and implementation strategies for both browser and server-side environments.TLDR• Unified Platform: Statsig integrates feature flags, experimentation, and analytics through a single data pipeline, eliminating data silos and ensuring statistical integrity• Dual SDK Architecture: Server SDKs download full config specs and evaluate locally (sub-1ms), while client SDKs receive pre-evaluated results during initialization• Deterministic Assignment: SHA-256 hashing with unique salts ensures consistent user bucketing across platforms and sessions• High-Performance Design: Global CDN distribution for configs, multi-stage event pipeline for durability, and hybrid data processing (Spark + BigQuery)• Flexible Deployment: Supports cloud-hosted, warehouse-native, and hybrid models for different compliance and data sovereignty requirements• Advanced Caching: Sophisticated caching strategies including bootstrap initialization, local storage, and edge integration patterns• Override System: Multi-layered override capabilities for development, testing, and debugging workflows