Free · Productivity · 5 of 7 tools · updated Oct 17, 2026
Free AI tools for AI notes & second brain
Obsidian is the strongest tool for AI notes & second brain you can use without paying, at 52/100. What you get for nothing: Free; Sync $4/mo. 5 of the 7 tools tracked for this job have a free tier, an open-source licence, or are free outright. It is also the top-ranked tool for this job overall, free or not.
Same evidence score as the ranking — GitHub stars, Hacker News mentions, release activity, free access — recomputed nightly, never sold. See all 7 tools for AI notes & second brain.
Top 3
evidence / 100
+ Your notes are plain files you own, and plugins like Copilot and Smart Connections let you chat with your vault using any model, including local ones.
− AI features require configuring third-party plugins and API keys yourself.
+ No bot joins the call, and the final notes combine your own jottings with what was actually said.
− Desktop-only capture means it cannot record a meeting you join from another device, and the free tier is a small trial.
+ Answers are grounded strictly in your uploaded PDFs, Docs, URLs and YouTube videos with citations, and Audio Overviews turn them into a two-host podcast.
− Sources are capped per notebook and the free tier limits daily queries and audio generations.
All 5, side by side
| Tool | Score | Pricing | What you get free | Platforms |
|---|---|---|---|---|
| Obsidian | 52 | Free | Free; Sync $4/mo | mac, windows, linux, ios, android |
| Granola | 27 | Free tier | Individual $18/mo | mac, windows, ios |
| NotebookLM | 16 | Free tier | Free; NotebookLM Plus via Google AI Pro $19.99/mo | web, ios, android |
 Notion AI | 11 | Free tier | Included in Business plan $20/user/mo (annual) | web, mac, windows, ios, android |
 Glasp | 10 | Free tier | no limits published | web, chrome-extension, ios |
A free tier counts, and so does an open-source licence you can self-host — both are in the table, so a tool that is only free for a trial is not here.
Head to head: Obsidian vs Granola