Open Source Zim Alternatives

IT's not so similar to Zim Desktop, it's really near to evernote/nixnote It can be a good replacement too

Joplin caters to a somewhat different user base: more simplistic, quicker, requires way less IT/wiki savvy just to operate daily. It also has pitch perfect syncing which is not Zim's cup of tea. Still, the moving parts are similar, and it can work as an alternative.

Zim is a wiki-type encyclopedia software. Standard notes is just a basic notes app.

If Zim isn't to your liking, CherryTree might be: open-source, stores data locally, supports instant search, interprets code blocks, and has more text editing features. The only thing it's not good at (yet) is attaching things by drag-n-drop. But that is in development, I hear.

wysiwyg , bug free, easy-to use and versatile interface, encrypted and un-encrypted mode, can import/export data from/to zim keynote html etc . Code box with syntax highlighting feature is nice. Also can import files image etc . Strictly hierarchical. More likely an outlining software.

Simplenote is much less functional than Zim (no rich-text, no attachment to notes) and although it does work on mobile, it syncs your data via web-facing servers on which your info is held unencrypted. In that respect your information is much more vulnerable to hackers and govt agencies than if you used Zim, stored the data locally and maybe - if you need - sync it with an end-to-end encrypted service like Spideroak, Tresorit or Seafile (Seafile encrypts file content, not metadata).

Free and free of problems. Just simple.

The single html file of TW is unbelievably simple and platform agnostic. File can be opened in any browser. There TW will open, edit, etc. Works just as well on a phone. File can be hosted/sync'd on DropBox or similar so you don't even need to download/upload (in the usual sense). Very smooth interface to boot. Robust support community constantly adding plugins.