Jan (43,864 Stars) 2026: The Offline-First AI Assistant Desktop App - Run Models Locally with OpenAI-Compatible API

Jan (43,864 stars) is the offline-first AI assistant for desktop - run open-source models locally with a clean UI and an OpenAI-compatible local API. Here is the complete guide.

💡 What You Will Learn

Jan (43,864 stars) is the offline-first AI assistant for desktop - run open-source models locally with a clean UI and an OpenAI-compatible local API. Here is the complete guide.

## The short answer **janhq/jan** (43,864 stars, TypeScript) is an offline-first AI assistant desktop app. You install it, download a model, and chat - fully offline. It also exposes an OpenAI-compatible local API server, so other tools (like Open WebUI or your scripts) can use the same local models. ## Why Jan stands out - **Offline-first**: models run 100% on your device - **Clean desktop UI**: Windows, macOS, Linux - **Model hub**: browse and download GGUF models in-app - **Local API**: OpenAI-compatible endpoint for integrations - **Extensions**: add tools and features via Jan extensions ## Getting started 1. Download Jan from https://jan.ai (Windows/macOS/Linux). 2. Open the app and go to the **Model Hub**. 3. Download a model (start with a 3B-8B quantized GGUF). 4. Start a conversation - it runs offline, no account needed. ## Using the local API Enable the local API server in settings, then: ```bash curl http://localhost:1337/v1/chat/completions \n -H "Content-Type: application/json" \n -d '{"model": "llama3.2", "messages": [{"role": "user", "content": "Hello"}]}' ``` Any OpenAI-compatible client can now talk to your local models. ## Practical tips - Try the extension marketplace for connectors (e.g. to cloud models when needed). - Keep the app updated - inference performance improves with each release. - For heavier models, close other apps or use a machine with 16 GB+ RAM. ## FAQ **Is it free?** Yes - open source (AGPL for the app). **Does it need a GPU?** No - it runs on CPU, and uses GPU when available. **Can I use it as a local OpenAI replacement?** Yes - the built-in API server makes it drop-in compatible with OpenAI SDKs.