API (1): LLM class from vllm import LLM # Example prompts. prompts = ["Hello, my name is", "The capital of France is"] # Create an LLM with HF model name. llm = LLM(model="openai/gpt-oss-20b") # Generate texts from the prompts. outputs = llm.generate(prompts) # also llm.chat(messages)] A Python interface for offline batched inference
API (2): OpenAI-compatible server $ vllm serve openai/gpt-oss-20b $ curl http://localhost:8000/v1/responses \ -H "Content-Type: application/json" \ -d '{ "model": "openai/gpt-oss-20b", "input": "tell me a 20 words story about a cat", }' A FastAPI-based server for online serving Server Client
Drop-in Compatible Server $ vllm serve openai/gpt-oss-20b 🆕 Multi-Modality Input API 🆕 Rerank, Pooling and Embedding API 🆕 Responses API 🆕 SageMaker API 🆕 Anthropic API 🆕 API for RL: Tokens-in-tokens-out 🆕 gRPC API 🆕 Omni Modality API
new KV Offloading Connector https://blog.vllm.ai/2026/01/08/kv-offloading-connector.html Up to 9x increase in throughput on H100, 2x-22x reduction in TTFT for cache hits Try with: --kv_offloading_backend native --kv_offloading_size <GB> 18 CPU Hit Rateが上がるとトークンスループットが向上 ブロックサイズが⼤きくなるとDMAでのスループットが向上
use Speculative Decoding? 21 Not a universal solution Speculative Decodingはコンピューティング能⼒ の余剰がある場合はメモリ帯域の節約に寄与する が、コンピューティング能⼒の余剰が無い場合は ロスに繋がる Use it for: ▸ RAG、エージェント、アシスタントなど レイテンシの要件が厳しいアプリケーション Avoid it if: ▸ バッチなどのthroughput-heavyな処理 ▸ 入力が長く、アウトプットが短い処理 (TTFTではなくTPOTを改善するため)
key vLLM features Comment and review PRs that are interesting to you. Join the discussion on RFCs. Check out “good first issue” tags. Give Us Feedback We’ll email you today’s recording as soon as it’s ready. Respond and tell us what we are doing right and what we can do better with vLLM office hours. Or comment on this slide! Join vLLM Developer Slack Ask questions and engage with us via Slack. Join here. Join Red Hat’s vLLM Mission Red Hat wants to bring open-source LLMs and vLLM to every enterprise on the planet. We are looking for vLLM Engineers to help us accomplish our mission. Apply here. Get involved with the vLLM Community 31