Second Brain vs Stacks

Second Brain is your offline-first personal knowledge management app. Capture every idea, note, and insight — and never lose a thought again. No ads. No tracking. No account required. Your data stays on your device. FEATURES: • Rich Notes — Write with Markdown support, add images, link notes together • Collections — Organize notes into collections with icons and colors • Tags — Tag anything for instant filtering • Daily Notes — One note per day, automatically created • Goals — Track personal goals with milestones and progress • Book Notes — Capture key takeaways from books you read • Quotes — Save your favorite quotes • Knowledge Graph — See how your ideas connect visually • Bi-directional Links — Link notes and see backlinks automatically • Full-Text Search — Find anything instantly • Favorites & Archive — Star important notes, archive the rest • Quick Capture — Capture thoughts from the home screen widget • Face ID / Touch ID — Lock your app for privacy • iCloud Backup — Optional, off by default • Export — PDF, CSV, Markdown • 15 Languages — English, Turkish, Spanish, German, French, Italian, Portuguese, Dutch, Polish, Arabic, Japanese, Korean, Chinese, Russian PRIVACY FIRST: Second Brain collects zero data. No analytics, no tracking SDKs, no servers. Everything lives on your device. PREMIUM (one-time purchase): Unlock unlimited notes, collections, Knowledge Graph, exports, Face ID, and home screen widgets with a single lifetime purchase.

Everything you save online ends up scattered — a restaurant buried in your Instagram saves, a recipe in a TikTok favourite, a hotel in a Safari tab you'll never find again. Stacks brings all of it into one place and organizes it for you. Share a link to Stacks from any app and it reads the page, works out what it is, and files it away: the restaurant into Food, the hotel into Travel, the outfit into Fashion — with a title, a summary, tags and a cover image, ready to find months later. SAVE FROM ANYWHERE • Share from Instagram, TikTok, Pinterest, Reddit, YouTube, X, Facebook or Safari — anything with a share sheet • Or paste a link straight into the app • Shared links are imported and organized in the background, before you next open the app ORGANIZED FOR YOU • Every save is categorized automatically — Food, Travel, Fashion, Fitness, Shopping, Learning and more • Tags, topics, summaries, places, brands and recipes pulled out of the page for you • Smart collections group related saves into a trip, a reservation, a concert, a birthday • Or build your own collections by hand FIND IT BY MEANING • Search understands what you meant, not just the words you typed • "Sushi in Tokyo" or "black outfit" surfaces the right save, even when those exact words aren't in it • Filter by category, platform, tag or collection MORE THAN A BOOKMARK • Map — every saved place on one map, exactly what you want before a trip • Calendar — put a save on a date and get a reminder when it matters • Notes and checklists on any save, for packing, shopping and planning • Favourites and an archive to keep the list clean PRIVATE BY DESIGN • No account. Nothing to sign up for • On iPhones with Apple Intelligence, saves are analyzed by Apple's on-device model; on every other iPhone an on-device fallback does the same job • Search runs on-device too — no query ever leaves your iPhone • No analytics, no ads, no tracking, no third-party SDKs, and no servers of ours for anything to be sent to Free, with no subscription and no in-app purchases.