Jan AI
by Jan (formerly Homebrew Computer Company)
Jan is an open-source, privacy-focused desktop application for running large language models locally, offering a ChatGPT-like interface that works fully offline and also supports connecting to remote APIs such as OpenAI or Anthropic. It is…
Definition
Jan is an open-source, privacy-focused desktop application for running large language models locally, offering a ChatGPT-like interface that works fully offline and also supports connecting to remote APIs such as OpenAI or Anthropic. It is built to give users a single interface for both local and cloud-hosted models.
Overview
Jan positions itself as an open-source alternative to hosted chat assistants, built around the principle that AI interaction should not require sending every conversation to a third-party server. The desktop app, available for Windows, macOS, and Linux, bundles a local inference engine (based on llama.cpp-style backends) so users can download open-weight models in GGUF format and run them entirely on their own hardware, with no internet connection required after the initial download. Unlike some local-only tools, Jan also supports 'remote' model providers: users can plug in API keys for OpenAI, Anthropic, Groq, Mistral, and other hosted services and switch between local and cloud models from the same interface. This makes Jan useful both as a fully offline assistant and as a unified front end for comparing or mixing local and hosted models in one place. Jan exposes an OpenAI-compatible local API server, so any tool or script built against the OpenAI API shape can point at Jan's local server instead and use locally running models as a drop-in replacement. It also supports extensions and a growing set of assistant configurations, letting users create custom personas or workflows around specific models. The project emphasizes data locality — conversation history and model weights are stored on the user's machine by default — and it is fully open source, allowing self-hosting, auditing, and community contributions. Jan sits in the same competitive space as GPT4All, LM Studio, and Ollama, differentiating primarily through its unified local-plus-cloud model switching and clean, ChatGPT-style UI.
Key Features
- Cross-platform desktop app with a ChatGPT-style chat interface
- Runs open-weight GGUF models fully offline on local hardware
- Also connects to cloud model providers (OpenAI, Anthropic, Groq, Mistral) via API keys
- OpenAI-API-compatible local server for use with existing tooling
- Model management UI for downloading, switching, and configuring local models
- Extension system for adding assistants and custom workflows
- Open-source codebase with local-first data storage
- No account required to use local models