happybook

Your PDFs, reading each other.

Happybook turns a pile of PDFs into a notebook: highlight the passages that matter and draw links between documents, so page 12 of one paper can point straight at the figure that answers it in another.

Open Happybook Free, works offline, no account needed. Sign in with a passkey to sync.

Notebooks of PDFs

Drop in a PDF to start a notebook, then keep adding sources as the project grows.

Cross-links

Select a passage, link it to a spot in any other PDF, and jump between the two in either direction.

Offline first

Documents and notes live on your device. Airplane mode is a reading room, not an error page.