Lexicon

An offline writing assistant for Windows, macOS and Linux with local grammar checks, AI rewriting through llama.cpp or Ollama, and no account requirement.

Alternative to:

Lexicon is a writing assistant and rich-text editor for people who want to proofread and revise drafts on their own computer. Grammar checks work without an AI model, while optional local AI tools help rewrite longer passages and whole documents.

Proofreading and review: LanguageTool checks spelling and grammar locally, with inline suggestions you can accept or dismiss, a personal dictionary, tone detection and readability scoring.
AI revision: Rewrite or shorten text, change its tone, generate summaries, or turn passages into key points, lists and tables, including across a whole document.
Writing workspace: The editor supports images, tables, code blocks and LaTeX math with live previews, alongside Focus Mode and local auto-save.
Import and export: Bring in plain text, Markdown or HTML, then export those formats or a PDF that leaves out the interface and proofreading marks.

Lexicon is free and open source under the MIT license. It runs on Windows, Linux and macOS, including Intel and Apple Silicon Macs. The bundled llama.cpp backend uses quantized GGUF models; an existing local Ollama server is an optional alternative.

The initial bundled-model download connects to Hugging Face. Once the model is downloaded, AI writing tools work offline, and the editor and proofreading tools work without that download. Documents stay on your machine, and you don't need an account. Windows installers are unsigned, and macOS builds are unsigned and not notarized, so operating-system security checks may block them.