Tiddly Research has been discontinued. Similar apps include Logseq, which is free and open source. Other options are Notesnook, Zettlr, Zim and CherryTree. You're spoiled for choice with Note-taking Tools like Tiddly Research: we list more than 50 alternatives for Mac, Windows, Linux, the web and iPhone.
Supernotes, is a new way to create notes and collaborate with your friends. Quickly create note-cards with diverse content from task lists to maths equations, with full markdown and LaTeX support. You can tag your cards, find relevant keywords, and sort your cards in an instant.
United Kingdom
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.
MindForger is a modern, free, open-source, privacy-focused and performance-driven Markdown IDE for creating, editing, and managing all types of notes.
Czechia
EU
A versatile, cross-platform worldbuilding app that can be used as a simple note-taking app, a private local wiki, a writing tool for a novel, or a TTRPG campaign manager.
United Kingdom
Imagine a hassle-free text-writing experience. Don't worry about saving files, complex markup, or accidentally deleted notes.
EstoniaEU
A markdown-based notes app for macOS, with simplicity and moderation.
United Kingdom
Notabase is a powerful and easy-to-use note-taking app for networked thinking. Connect your ideas together and write more effortlessly.
Relanote is ? note-taking app that combines both hierarchical and non-hierarchical (wiki-style) note-taking. By leveraging the power of both methods, Relanote adapts to your way of thinking and allows you to create your personal knowledge base.
Windi is a knowledge management app that helps you take short notes, make sense of them, and share with your communities.
United States
