vLLM 0.32.0 and SGLang 0.5.22 architecture comparison

This article examines the internal architecture of LLM serving engines, comparing the process layouts, scheduling mechanics, and memory management strategies of vLLM and SGLang. The author analyzes how both engines divide responsibilities across layers like the API frontend, scheduler, KV memory manager, and model executor, highlighting the trade-offs between vLLM's centralized engine core and SGLang's per-rank scheduler model. Additionally, the post explores single-request latency metrics and discusses upcoming changes with experimental Rust frontends. Open article →