Brainio turns every note into a visual mind map. Write in Markdown, press Tab to indent and create branches, switch between text, split, and mind map views with one click. Built-in knowledge graph shows how all your documents connect. Collaborate in real time with live cursors. Link documents with bidirectional backlinks. Connect your AI assistant via MCP. We launched Brainio 5 years ago. We rebuilt it from scratch and made it completely free. No document limits, no paywalls.