Top 3 Open-Source Alternatives to Defter Notes private beta

Logseq is a local-first, non-linear, outliner notebook for organizing and sharing your personal knowledge base.

Infinite Canvas Encrypted Note-taking

Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.