Meta has shipped a new release of CacheLib — tagged v2026.05.25.00 on May 25 — marking the project’s return after approximately two years without a public update. CacheLib is an Apache 2.0-licensed C++ pluggable in-process caching engine that Meta originally open-sourced in September 2021, when the motivation was offsetting rising DRAM costs by pairing it with non-volatile memory to build DRAM/NVM hybrid cache tiers. As of the 2021 launch, the engine was already deployed across more than 70 large-scale Meta systems spanning the social graph, CDN, storage, and key-value caches. The timing of the 2026 revival is noted by Phoronix as particularly apt: DRAM prices are substantially higher than they were at the original open-source launch, driven by demand from the AI infrastructure buildout.
No public changelog or release notes accompany the v2026.05.25.00 tag beyond automated file hashes; the release was generated via Meta’s internal TagIt tooling. CacheLib continues to describe itself as a “pluggable caching engine to build and scale high performance cache services,” and the project ships alongside CacheBench, a benchmarking tool for evaluating caching performance across diverse production workloads. The source code is available at GitHub and the project website is at CacheLib.org.