You can keep notebooks stored in plain-text and have them synchronized with a directory on your mobile device, SD card, Dropbox, or over WebDAV.
Platforms
- Android
- Android Tablet
United States



Apps similar to Opal include Orgzly, which is free and open source. Other options are OmniOutliner, Orgzly Revived, Zavala and Visual Outliner. In total there are nine Note-taking Tools like Opal for Mac, iPhone, Windows, iPad and Android.
You can keep notebooks stored in plain-text and have them synchronized with a directory on your mobile device, SD card, Dropbox, or over WebDAV.



OmniOutliner is a start-to-finish writing app. Perfect for collecting information, outlining Big Ideas, adding structure to any sort of writing, and much more. From grocery lists to email drafts to long-form composition.







Zavala is a modern take on a traditional outliner. It supports all the things you want in a Mac app like multiple windows, keyboard shortcuts, a customizable toolbar, and a full menu bar.




Visual Outliner is an outliner software for Windows, and it uses OPML as native file format. It's not just another tasklist application, but a real outliner editor that can be used to write, view, modify, and maintain hierarchically arranged text.




The beautifully crafted outliner for your Mac. Keep ideas structured and collected every day.




Dashword is by far the most convenient and user-friendly tool for creating any semantic network, be it your business idea, an abstract of a lecture on computer science, a script for a movie or a recipe for your favorite dish.




Password Locker is the only iOS Screen Time blocker that completely eliminates workarounds. It helps you stay focused by patching all known loopholes in Apple's Screen Time, ensuring you can't disable your app restrictions on impulse.

WaitToUnlock helps you make iPhone Screen Time actually work by guiding you to set a passcode you won't remember and delaying access when you need it back.


