Not3.io is described as 'A web application that allows you to easily create notes on the web' and is an website in the News & Books category. There are more than 25 alternatives to Not3.io, not only websites but also apps for a variety of platforms, including Windows, Android, iPhone and iPad. The best alternative is Joplin, which is both free and Open Source. Other great sites and apps similar to Not3.io are Microsoft OneNote (Freemium), Evernote (Freemium), Simplenote (Free, Open Source) and Cryptee (Freemium, Open Source).
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, can be copied, tagged and modified either from the applications directly or from your own text editor.
Colorful & powerful sticky notes app for Windows & Phones. Set reminder alarms, attach them to any website or document, organize them using folders/tags, sync sticky notes between devices & send notes across LAN or to any contact across the globe.