DocBlocks is a free, open-source markdown editor for Mac, Windows and Linux, plus the web, VS Code and the command line. Your documents stay plain .md files in your own folders, and one file can become a Word doc, PDF, slide deck, e-book or video. New: opt-in AI that can run entirely on your computer. It reviews drafts, writes and rewrites, draws diagrams, words your slides, makes summaries, quizzes and flashcards, and takes dictation or reads aloud. No account, no lock-in.