DeepSeek packed LLM engine into 1200 lines of Python code

The DeepSeek team presented nano-vLLM. This is a lightweight and compact engine for running large language models. Which could change perceptions about code efficiency. Amazingly, all functionality fit into just 1200 lines of Python code! This is true technological minimalism in the world of artificial intelligence. Traditional engines like this, for all their power, often suffer from an overloaded codebase. Which makes their modification a real trial for developers. Nano-vLLM solves this problem by offering a simple but powerful tool without unnecessary complexity. The code is open.

At the same time, functionality is not sacrificed. The engine supports prefix caching, tensor parallelism, compilation with torch compile and working with CUDA. Tests on a laptop graphics card RTX 4070 with 8 GB memory showed impressive results. When running the Qwen 3.0 model with 6 billion parameters, DeepSeek’s engine processed 133966 tokens in 93.41 seconds. Which is even faster than the original vLLM engine.