Obsidian

A free, local-first note-taking app that stores everything as plain Markdown files on your own device, with backlinks and a graph view for connecting ideas. Good for building a personal knowledge base, class notes, or research.

Best for: A private, offline second brain

What you get

• Core app is completely free with no limits: unlimited vaults, no sign-up required, works offline
• Includes graph view, Canvas, Bases, and thousands of community plugins at no cost
• Optional paid add-ons: Sync $4/mo annual ($5 monthly); Publish $8/mo annual ($10 monthly)
• Students, faculty, and nonprofit staff get 40% off Sync and Publish

How students use it

• Link lecture notes into a personal knowledge graph
• Write in plain Markdown files you actually own
• Study from your own connected notes, no account needed