mistral.rs is an inference engine for large language models that runs locally and exposes models behind OpenAI and Anthropic-compatible APIs. It serves as a multi-model serving platform, capable of loading several models in a single server process with per-request routing and on-demand loading and unloading. The engine supports multimodal inference, processing text alongside images, video, audio, and speech inputs, and includes a quantized model deployment runtime that reduces memory use and speeds up inference on consumer hardware.
The project distinguishes itself through an agentic tool execution framework that runs server-side tools like code execution, shell commands, and web search in an automated loop during model generation, with session state persistence. It provides an in-process inference engine that can be embedded directly into Rust or Python applications without a separate server process, and includes an in-situ quantization engine that converts model weights to lower precision at load time with per-layer tuning. The system supports structured output constraints, forcing model output to conform to JSON Schema or grammar specifications during decoding, and offers automatic architecture detection that identifies model type, quantization format, and chat template from a Hugging Face model ID.
The platform includes capabilities for managing LoRA adapters, composing models as mixture-of-experts configurations, and running distributed inference across multiple GPUs or nodes using tensor parallelism and ring transport. It provides a built-in web chat interface, supports speculative decoding with a smaller assistant model, and offers benchmarking, logging, and Prometheus metrics for monitoring. The project can be run from a configuration file, with options for customizing build processes, tuning hardware settings automatically, and managing model caches.
