Profiling Server Core: How we cut memory usage by 85%

Earlier this year, Statsig launched Statsig Server Core, a revamped version of their Server SDKs using a unified Rust evaluation engine to optimize performance across various platforms. The focus was on reducing memory usage, and through rigorous testing, significant improvements were made compared to the legacy SDKs. Initial versions of Server Core exhibited higher memory consumption and volatility, but after optimizations, the latest version showed an 84% reduction in baseline and a 68% reduction in peak memory usage. Key enhancements included string interning, shared DynamicReturnable objects, and streaming deserialization, which collectively minimized memory spikes. These optimizations are particularly impactful as they apply universally across all SDKs backed by the Rust core, ensuring a leaner, more scalable, and cost-efficient performance for users. The results validate the shift from language-specific SDKs to a unified core, demonstrating a smaller memory footprint, faster operations, and easier maintenance across different environments.