Our verdict: the most straightforward way to run open LLMs entirely on your own machine — private by default, needing no account and no cloud, with signing and audit status we could not independently confirm.
Ollama is an open-source tool that lets you download and run open large language models — including Llama, Gemma, Qwen, DeepSeek and gpt-oss — 100% locally on your own hardware. A single command pulls a model from its 200+ model library and runs it, with GPU acceleration on NVIDIA, AMD and Apple Silicon.
Because local models run entirely on-device, Ollama works fully offline once a model is downloaded and your prompts never leave the machine — nothing is collected or used for training. It is a CLI-first tool that also ships a desktop chat app for macOS and Windows, plus a local REST API with OpenAI- and Anthropic-compatible endpoints. Optional cloud models are reachable through the same API, but those send content to Ollama's servers.