Jan
Open-source offline ChatGPT alternativeOpen-source desktop app that runs LLMs fully offline as a private ChatGPT alternative, with an OpenAI-compatible local API and optional cloud models.
- Maker
- Menlo Research
- Founded
- 2023
- Pricing
- Free tier
- Last checked
- October 2026
Verdict
Open-source desktop app that runs LLMs fully offline as a private ChatGPT alternative, with an OpenAI-compatible local API and optional cloud models.
Score breakdown
vs LM Studio, the category leaderPrivacy-minded users who want a clean, open-source desktop ChatGPT alternative that runs models locally.
Key features
- Runs open-source LLMs fully offline after the initial model download
- Built-in model hub for downloading and managing GGUF models
- OpenAI-compatible local API server (default port 1337)
- Optional connections to OpenAI, Anthropic, Gemini and other OpenAI-compatible endpoints
- Persistent, locally stored multi-thread chat history
- Extension/plugin system for community add-ons
- GPU acceleration (CUDA, ROCm, Apple Metal) plus CPU-only inference
- Cross-platform desktop app built with Tauri (macOS, Windows, Linux)
Strengths
- +Completely free and open source (Apache-2.0) with no subscriptions or token limits
- +True offline operation — inference runs locally with data kept on-device
- +Built-in OpenAI-compatible local API server makes Jan a backend for other tools
- +Unifies local and cloud models (OpenAI, Claude, Gemini and others) in one interface
Weaknesses
- −Model quality and speed are bound by your own hardware
- −Desktop only — no mobile app
- −UI is less polished than some commercial alternatives, and a few features remain 'coming soon'
- −Past security issues were reported (and addressed); large model downloads require patience
Overview
Overview
Jan is an open-source (Apache-2.0) desktop application, first released in 2023 and maintained by Menlo Research, that positions itself as a private, offline alternative to ChatGPT. It downloads and runs open-source models locally through a built-in model hub, stores chat history on-device, and can also connect out to cloud providers like OpenAI, Anthropic and Google when you want them — all from one interface. With 43k+ GitHub stars and millions of downloads, it has a sizable community.
A defining feature is its built-in OpenAI-compatible API server (on port 1337), which lets other tools and IDEs use Jan as a local LLM backend. Built with Tauri, it runs across macOS, Windows and Linux and supports GPU acceleration as well as CPU-only inference. It is less polished than some commercial GUIs and a handful of advanced features are still in progress, but the privacy story and openness are strong.
Key Benefits
- Open and free: Apache-2.0 with no usage caps — you own the stack.
- Offline-first privacy: Conversations and inference stay on your device by default.
- Local API backend: The OpenAI-compatible server turns Jan into infrastructure other apps can call.
- One interface, many models: Switch between local and major cloud models without leaving the app.
Use Cases
- Private daily assistant — A ChatGPT-style experience that runs without sending data to the cloud.
- Local backend for tools — Use Jan’s server as a drop-in OpenAI endpoint for IDEs and scripts.
- Hybrid local/cloud workflows — Default to local models and reach for a frontier API only when needed.
- Learning local LLMs — A friendly GUI for downloading and comparing open models.
Pricing
Checked October 2026 · USD- Full app under Apache-2.0
- Unlimited local inference and model downloads
- Local API server and cloud-model connections (bring your own keys)