mdflux

Readest opens EPUB, MOBI, AZW3, FB2, CBZ, TXT, and PDF files across macOS, Windows, Linux, Android, iOS, and the web. Readers can switch between scrolling and paginated layouts, search within books, add bookmarks, highlights, and notes, look up terms, or place two documents side by side. It is designed for people who want a consistent reading workflow across several device types.

TagSpaces is an offline desktop application for browsing, tagging, searching, and managing local files on Windows, Linux, and macOS. Tags can live in filenames or sidecar metadata, while built-in tools handle notes, task lists, and common audio or video playback. Its browser extension saves web pages or screenshots locally, so the core workflow does not depend on a cloud service or internet connection.

ONLYOFFICE Desktop Editors is an open-source desktop suite for Windows, Linux, and macOS that works with documents, spreadsheets, presentations, PDFs, PDF forms, and diagrams without an internet connection. It supports Office Open XML files and can connect to cloud services for collaboration, while also offering signatures, password protection, plugins, and AI assistants. The project is licensed under GNU AGPLv3.

Every PDF brings common document work into a Windows and macOS desktop application. Users can add text, signatures, images, and checkboxes, convert files, split or merge pages, apply watermarks, reorder pages, and add or remove password protection. Because its macOS code signature changed, users on older releases must manually install version 2.0.2 or later once before automatic updates will work again.