Anytype

Anytype is a local-first, end-to-end encrypted knowledge base that works as a private alternative to Notion, storing everything on your devices and syncing over an encrypted peer-to-peer network. Only you hold the keys so the team behind it cannot read your pages or databases. It is run by a Swiss-registered association with a development hub in Berlin. The honest caveat is licensing: the clients are source-available under Anytype's own non-OSI license rather than true open source, which limits independent audit compared with the fully open options. There is also no web app so you will need the desktop or mobile client.