Synapse PDF

Synapse PDF is a complete study and knowledge workspace for macOS. Instead of paying for multiple apps, it combines advanced PDF annotation, study session tracking, and 19+ built-in utilities (merge, split, OCR) into one native app. Standout features include "Link It" to build knowledge maps across documents, and "Sum It" to export all highlights instantly. Say goodbye to expensive subscriptions—available with a 7-day free trial and a Lifetime license!