ModelRefs / vLLM — AI Glossary

vLLM — AI Glossary

An open-source, high-throughput LLM inference engine built on PagedAttention and continuous batching. Self-hosting open-weight models with real concurrency

Overview

vLLM is the de-facto open serving stack for open-weights models, supporting tensor parallelism, speculative decoding, LoRA hot-swap, and OpenAI-compatible APIs. Widely adopted in production for self-hosted Llama, Mistral, and Qwen deployments.

Reference details

Topicinfrastructure
Last reviewed2026-06-24

Example: Why continuous batching matters

With static batching, a batch of eight requests waits for the slowest to finish before any slot frees. Continuous batching evicts each sequence as it completes and admits a new one immediately, so the GPU is not idling on finished slots. That scheduling difference, not a faster kernel, is where most of the throughput gain comes from.

Commonly confused with

vLLM is an inference server, not a model and not a framework for building applications. It serves open-weight models over an OpenAI-compatible API. It does not fine-tune, does not orchestrate, and is not an alternative to a gateway — those sit at different layers.

When to use it

Reach for it when:

  • Self-hosting open-weight models with real concurrency
  • You need PagedAttention or LoRA hot-swap at serving time
  • You want an OpenAI-compatible surface over your own hardware

Reach for something else when:

  • You use hosted APIs — the provider already runs something like it
  • Single-user or batch workloads, where a simpler runtime is easier to operate
  • Nobody owns GPU operations; a serving stack is infrastructure to run

Continue your research

Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to vLLM — AI Glossary.

Frequently asked questions

What is vLLM?

An open-source, high-throughput LLM inference engine built on PagedAttention and continuous batching.

What concepts are related to vLLM?

Closely related concepts include paged attention, continuous batching, inference.