Jan

✓ Editorially verified

Open-source desktop ChatGPT alternative that runs local LLMs and routes to cloud providers from one app.

Free· Free and open source; bring-your-own keys for cloud modelsWritingMulti-model (local open-weights + OpenAI/Claude/Gemini via API)

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Best for

Pick Jan if you want a single desktop app to chat with local open-weight LLMs and also tap OpenAI/Claude/Gemini through your own API keys.

Skip if

Skip it if you want a polished, zero-setup hosted assistant with built-in memory, web search and multimodal features out of the box.

Jan is an open-source desktop application that positions itself as a privacy-first alternative to ChatGPT. It runs local LLMs on your own machine (Llama, Mistral, Qwen, DeepSeek, Gemma, Kimi and others via the Hugging Face hub) and can also route prompts to commercial APIs like OpenAI, Anthropic Claude and Google Gemini through your own keys. Everything lives on your device unless you choose otherwise, which is the main selling point versus the cloud SaaS chat tools it competes with.

The project is free, MIT-style open source, and has accumulated north of 5 million downloads and 40K+ GitHub stars, so it is one of the more mature entries in the local-LLM client space alongside LM Studio and Ollama. It is best suited for developers, security-conscious knowledge workers and tinkerers who want a unified chat UI over both local and remote models without paying a subscription. Jan also exposes an OpenAI-compatible local API server, which makes it usable as a drop-in backend for other tools that expect the OpenAI SDK.

Caveats: as with any local-LLM front end, performance depends entirely on your hardware (Apple Silicon and discrete GPUs fare best), and the polish gap with hosted ChatGPT/Claude apps is real on features like long-term memory, web browsing and multimodal input — though a memory feature is on the public roadmap.

Editor's take

Jan is the most credible open-source ChatGPT alternative on the desktop right now, sitting in the same niche as LM Studio but with broader cloud-provider routing. It is the right pick if privacy or model choice matters more than the last 10% of UX polish.

— The AI Tool Bible editorial team

Pros

✅ Genuinely open source with an active community and 40K+ GitHub stars
✅ Runs models fully locally for privacy; no data leaves the device by default
✅ Unifies local LLMs and cloud APIs (OpenAI, Anthropic, Gemini) in one UI
✅ Exposes an OpenAI-compatible local server for use as a backend
✅ Free with no subscription or per-token markup

Cons

⚠️ Local inference speed is bottlenecked by your CPU/GPU and RAM
⚠️ Feature polish lags hosted apps (memory, browsing, multimodal still maturing)
⚠️ Setup and model management has a learning curve for non-technical users