Heptabase

Heptabase is a visual knowledge base with AI, starting at $8.99/month for individuals building a lifelong knowledge base. It combines whiteboards, cards, and an AI tutor to help you deeply understand hard subjects. Core capabilities include block-based editing, bidirectional links, PDF and YouTube annotation, and integrations with Readwise and Zotero. AI features offer chat, tutor, and credits (100–8100/month across plans) with access to premium models. The tool runs on Mac, Windows, Linux, iOS, and Android. Ideal for students, researchers, and lifelong learners who need to organize research, learn complex topics, and build a connected knowledge base.