Obsidian

Obsidian is the note-taking tool for people who take data ownership seriously. Your notes are plain Markdown files — open them in any editor, grep them from the terminal, sync them with git. There's no vendor to disappear, no proprietary export, no subscription required to read your own writing. The tradeoff is a real learning curve: Obsidian rewards configuration, not convenience. But for solo researchers, developers, and long-term thinkers who want a knowledge base that compounds over years, nothing else comes close.