Comet vs Heptabase

Comet has no write-up on Specifiction yet; its figures are above.

Heptabase is a visual knowledge base for students, researchers, and lifelong learners. Whiteboards and cards support visual thinking, while a block-based editor, bidirectional links, PDF annotation, daily journals, and a web clipper help organize material. Its AI can explain sources, take notes, and organize a knowledge base from PDFs, YouTube, notes, and journals. Heptabase supports web, Windows, macOS, Linux, iOS, Android, and a Chrome extension, and lists integrations with Readwise and Zotero. The free plan is available through collaboration, allowing edits to shared whiteboards and cards but excluding personal libraries, journals, tag databases, tasks, highlights, and AI features. The desktop app stores data locally, and notes and files are accessible offline. For AWS cloud storage, the company describes encryption in transit and at rest, but not end-to-end encryption. After a subscription or trial ends, users can access and export content indefinitely; creating or editing notes requires renewal. Paid plans start at $8.99/user/mo (annual), with a 7-day trial.