Apps to Hierarchical Structure

Elephant is a portable, privacy-focused note-taking application featuring a classic, intuitive interface. It supports robust note organization, rich text formatting, markdown, and offline access. With capabilities like image insertion and secure cloud synchronization, Elephant is designed for users needing a reliable and versatile digital notebook.

ThinkComposer is a highly flexible visual modeling tool designed for users to create rich, structured diagrams based on their specific domain knowledge. It facilitates the organization and visualization of complex information through various diagram types and hierarchical structures, enabling deep understanding and effective communication of ideas.

Gruik is a powerful, free, and open-source note-taking service designed for users who value privacy, organization, and control over their data. Offering robust features like hierarchical organization, offline access, rich text formatting, and synchronization options, it provides a flexible platform for managing notes, ideas, and personal knowledge wikis.

MyTetra is a versatile, cross-platform information manager designed for collecting, organizing, and managing various types of data. It excels as a portable note-taking application, personal information manager, and notebook, offering a robust outliner and rich text editing capabilities.

OpenProject is a powerful, web-based open-source project management software designed for teams of all sizes. It offers comprehensive tools for managing projects, tasks, teams, and communication in one centralized platform. Ideal for organizations prioritizing collaboration, flexibility, and data control.

Piggydb is an open-source web notebook application designed for building and managing knowledge bases, either individually or collaboratively. It emphasizes structured organization through hierarchical tagging and concept mapping.

Org-mode is a powerful and flexible mode for GNU Emacs, designed for note-taking, project planning, to-do list management, and authoring documents. It utilizes simple plain text files with intuitive markup.

KeepNote is a versatile note-taking application designed for organizing information in a hierarchical structure. Available on Windows, Linux, and macOS X, it features robust organization tools, including a tree-like outline, wiki-like linking, and support for embedded files and images. Although discontinued, its local storage and rich features make it a compelling tool for detailed note-taking and research.

Wekan is a free and open-source Kanban board application designed for collaborative task management. Based on the principles of Kanban, it offers a visual way to organize work, track progress, and improve workflow efficiency for individuals and teams.

RedNotebook is a free and open-source desktop journal and diary application offering a clean interface and features for organizing notes, thoughts, and ideas with a calendar view, tag search, and basic text formatting.

OpenNote is a free and open-source web-based note-taking application designed as an alternative to commercial offerings like OneNote and Evernote. It focuses on providing a lightweight yet feature-rich environment for organizing your thoughts and information.

CherryTree is a powerful, free, and open-source hierarchical note-taking application. It allows you to organize your thoughts, ideas, notes, and code snippets in a tree-like structure with rich text editing and syntax highlighting.

wikidPad is a free and open-source wiki-like notebook application that allows you to store your thoughts, notes, and snippets of information in a highly organized and cross-referenced manner. Its strength lies in the effortless creation of links between pages, making it easy to navigate and connect related ideas.

Freeplane is a powerful and free mind mapping software that allows users to organize ideas, create outlines, and manage information in a hierarchical structure. It leverages the power of visual organization to facilitate brainstorming, project planning, and knowledge management.

Leanote is a versatile self-hosted note-taking application that blends rich text editing with Markdown support. It offers seamless synchronization across multiple devices and features built-in blog publishing capabilities, making it a powerful tool for both personal information management and content creation.

Redmine is a robust and flexible open-source project management web application designed to help teams manage projects, track issues, and collaborate effectively. It offers a wide range of features, including multi-project support, Gantt charts, time tracking, and extensive customization options through plugins and themes.

Zim is a powerful, open-source graphical text editor designed for maintaining a personal wiki or notebook. It allows users to organize notes, ideas, and various types of information in a hierarchical, interlinked structure, similar to a wiki.

FreeMind is a robust, open-source, and free mind mapping software written in Java. It's a versatile tool for brainstorming, organizing thoughts, managing projects, and structuring knowledge hierarchically, providing a flexible canvas for visual thinking.

Laverna is a privacy-focused, open-source note-taking application designed for secure personal information management. It offers a robust Markdown editor, strong encryption capabilities, and offline access, making it an ideal solution for users prioritizing data privacy and a seamless note-taking experience across devices.

WinDirStat is a free and open-source disk usage statistics viewer and cleanup tool for Microsoft Windows. It visually represents disk space usage with a treemap display, helping users identify large files and folders to free up space.