AI writing assistant that can run on my own computer without sending text to the cloud

Yes—Jan is probably the easiest place to start. It’s a desktop AI assistant that runs downloaded models on your computer and can work offline; just choose a local model, not a cloud provider. (docs.jan.ai)

Other good options:

• LM Studio — straightforward for downloading and chatting with local models; its documentation says prompts and documents stay on your device when using downloaded models, and it can work offline after setup. (lmstudio.ai)
• Ollama — another local option, especially if you’re comfortable with a little setup; it also offers an app interface. Make sure you select a local model rather than a cloud-hosted one. (ollama.com)

For writing, you can ask a local model to rewrite, proofread, summarize, brainstorm, or adjust tone. Local models may be less capable than top cloud assistants, and speed depends on your computer.

For extra assurance: download the app and model, then disconnect from the internet and test it. Once the model is installed, these tools can run offline. Which one I’d suggest—and which model will run comfortably—depends on whether you use Windows, Mac, or Linux and how much memory your computer has.

Here are the main options, depending on how much setup you want.

Easiest: a desktop app with a chat window

• Jan is a good fit for privacy. One source calls it the privacy-first, fully offline desktop option with an open codebase.
• LM Studio has the most polished interface. It's a desktop app with a built-in model browser: search, download with one click and chat, no terminal needed. The catch: Apple Silicon only, macOS 14 or newer. Intel-based Macs are not supported.
• GPT4All is another simple option. It ships built-in document chat (LocalDocs).

Writing-focused tools

• Obsidian plus a local-model plugin. If you already write in Obsidian, Obsidian AI LLM and Obsidian Copilot are listed as free, open-source, and offline-capable, with local models.
• Elephas (Mac). It supports both cloud and local models. When configured with a local model (via Ollama or LM Studio), it works offline for AI-assisted writing, summarization, and editing across your Mac apps. One comparison table marks its offline status as only "Partial," so check what it does with no network before you rely on it.
• Ollama + your favorite editor. This is the DIY route. One guide describes Ollama (a local LLM runner) paired with a text editor like VS Code, Obsidian, or Scrivener. You download open-source models (Llama 3, Mistral, DeepSeek, Qwen), run them on your own GPU or CPU, and generate text through a local API. Setup is a terminal command: install Ollama for macOS, Windows, or Linux, open a terminal, and run the sample command from the official quickstart.

Hardware
LM Studio recommends 16 GB of RAM for common supported setups and says 8 GB Macs may work with smaller models and modest context sizes. A smaller quantized model is the usual choice if memory is tight.

Checking that nothing leaves your machine

• Some local tools offer optional cloud models. For Ollama, set OLLAMA_NO_CLOUD=1 to switch them off and keep everything local.
• A simple test: download your model, turn off Wi-Fi, and confirm the assistant still works.

My suggestion: If you're on a Mac with Apple Silicon and want a simple start, try LM Studio with a model around 7–8B parameters. If you want a writing tool built into your workflow, try Obsidian with a local plugin or Elephas. Windows and Linux users can use Jan or GPT4All. Note that some of these sources are vendor blogs and roundups, so test a tool on a sample document before committing.

You can run AI writing assistants entirely on your own computer, ensuring that your text, notes, and sensitive documents never leave your machine.

To do this, you generally need two components:

1. A Model Runner: The software that "runs" the AI on your hardware.
2. An Interface: The application (like a chat window) you use to interact with the AI.

Recommended Tools

These tools are user-friendly, popular in 2026, and allow for a private, offline setup:

• Ollama: The most popular "engine" for running AI models locally. It is simple to install and works on Windows, macOS, and Linux. You can use it alone via the terminal or pair it with an interface.
• LM Studio: An excellent choice if you prefer a "point-and-click" graphical interface. It makes downloading and running different AI models very straightforward without needing to use a command line.
• AnythingLLM: Highly recommended if you want to chat with your own documents (PDFs, text files, notes). It has a built-in "local-first" design, making it ideal for private research or writing projects.
• Jan.ai: An open-source, user-friendly application that prides itself on being 100% offline and zero-telemetry.

How to Get Started

1. Download a "Runner": Download and install Ollama or LM Studio.
2. Select a Model: Within these apps, you can browse and download models (like Llama 3, Qwen, or Mistral). For writing tasks on standard home computers, models in the 7B to 12B parameter range are usually the best balance of speed and intelligence.
3. Go Offline: Once the model is downloaded, you can turn off your Wi-Fi or disconnect from the internet entirely. The AI will continue to function normally because all processing is happening on your local CPU or GPU.

Important Considerations

• Hardware: Running AI locally requires decent RAM (8GB is the minimum for small models, 16GB+ is recommended). If you have a computer with a dedicated graphics card (GPU) or an Apple Silicon Mac (M1/M2/M3/M4 chips), the performance will be significantly faster.
• "Model" vs. "Tool": Remember that the software (like LM Studio) is just the "player," and the AI model (like Llama 3) is the "data" it plays. You can swap models in and out to see which one performs best for your specific writing style.
• No Cloud Sync: Because these tools are truly local, your data will not sync across your devices automatically unless you set up a custom, private network solution.

Jan is a good place to start: it’s a free, open-source desktop app for Windows, macOS, and Linux. Choose a local model—rather than a cloud model—and once it’s downloaded, you can use Jan offline; its local-model chats stay on your computer. ¹³

Another option is LM Studio, which runs downloaded models locally and says its chats and document processing stay on-device. ¹² It can work offline after you’ve downloaded a model. ¹⁵

Getting started: install either app, download a small model, then disconnect from the internet and test a writing task—such as revising a paragraph. A smaller model is usually easier for a regular laptop to run, though the quality and speed depend on your computer. ²

For the strongest privacy assurance, stick to local models and check the app’s settings to ensure you haven’t selected a cloud provider.