2SBrain - AI Second Brain

Turn scattered notes, PDFs, and ideas into a living knowledge graph. Your AI-powered second brain that learns with you — and answers when you ask.

2SBrain — Your Second Brain for Work, Study, and Life

Stop losing brilliant ideas in folders you'll never open again. 2sbrain turns every document, note, and insight you collect into one connected knowledge graph you can actually talk to.

Upload a PDF, scan a page with your camera, paste a link, or jot down a quick note — 2sbrain reads it, understands it, and weaves it into the knowledge you've built so far. The more you feed it, the smarter your second brain becomes.

A SECOND BRAIN THAT THINKS WITH YOU • Drop in any document — research papers, reports, meeting notes, articles, textbooks • AI extracts the key concepts and connects them to what you already know • Watch your personal knowledge graph grow with every upload • Auto-generated summaries, glossaries, and quick Q&A for every document • Built-in quiz mode to test what you've actually absorbed

CHAT WITH YOUR OWN KNOWLEDGE • Ask questions in plain language — get answers drawn from your own library • Real-time streaming responses with sources you can trace back • Full conversation history, organized by session • Save the best answers as insights — they automatically reinforce the related concepts in your brain

A LIVING KNOWLEDGE GRAPH • See how ideas connect across documents, notes, and conversations • Obsidian-style wiki links between concepts, built automatically • Self-healing graph fills in missing pieces and groups related topics into maps • Track which ideas matter most to you over time

POWERFUL DOCUMENT TOOLS • Scan paper documents with your camera and turn them into searchable knowledge • Read PDFs and images with smart text selection • Tap any word to look it up instantly — or save it to your vocabulary notebook • Rich text editor for capturing thoughts on the fly • Organize everything into folders, grid or list view, your choice

LANGUAGE LEARNING, BUILT IN • Multi-language dictionary: English, Vietnamese, Chinese (Simplified & Traditional), Japanese, Korean, German • Personal vocabulary notebooks organized by topic • Flashcard mode with flip and swipe for daily review • Auto language detection — just tap a word and learn

WORKS EVERYWHERE, ANYTIME • Full offline support — your knowledge is always with you • Seamless sync across devices once you sign in • Start anonymously, sign in later — nothing is ever lost • Sign in with Email, Google, or Apple

WHO IT'S FOR • Researchers and students building a long-term knowledge base • Knowledge workers drowning in PDFs, reports, and meeting notes • Lifelong learners who want their reading to actually stick • Language learners who want vocabulary tied to real context • Anyone tired of bookmarks they'll never revisit

2sbrain isn't just storage — it's a thinking partner that grows with you. Every document you read, every insight you save, every question you ask makes your second brain a little sharper. Start with one note today, and watch a personal knowledge universe take shape.

Download 2sbrain and start building the brain you wish you'd always had.