Windows Softwares to Extensible by Plugins/Extensions

Nightingale is a highly customizable cross-platform audio player with a focus on extensibility, featuring a beautiful interface, a wide array of supported formats, and tools like media library management, podcast playback, and integrated web browsing.

CodeLite is a free, open-source, and cross-platform Integrated Development Environment (IDE) designed specifically for C, C++, PHP, and JavaScript (Node.js) development. It provides a feature-rich environment to streamline the coding process for these languages.

Gajim is a free and open-source instant messaging client for the XMPP protocol. Built using the GTK+ toolkit, it offers a wide array of features for secure and flexible communication, including encrypted chat, group conversations, multi-protocol support via gateways, and extensive customization options.

Delphi is a powerful Object Pascal IDE and component library for developing native applications across multiple platforms, including Windows, macOS, iOS, and Android. It emphasizes rapid application development with a focus on high-performance, compiled executables.

Nylas Mail, an extensible open-source email client, offers a unified inbox, robust search, and calendar integration. It supports multiple accounts and provides features like email tracking and undo send, aiming to enhance productivity and email management for users.

Haroopad is a discontinued markdown-enabled document processor designed for creating web-friendly content. It offers a distraction-free writing environment with live preview and syntax highlighting, making it suitable for bloggers, writers, and developers.

The Bat! is a secure and powerful email client for Windows designed for users who prioritize privacy, speed, and efficient email management, especially for handling large mail volumes.

ZOC is a professional terminal emulator designed for Windows and macOS. It offers a wide range of terminal emulation types and robust features for secure shell (SSH) and Telnet connections, scripting automation, and file transfers. It's a reliable tool for system administrators, network engineers, and developers.

WordWeb is a comprehensive offline English dictionary and thesaurus for Windows, macOS, iOS, and Android, offering definitions, synonyms, antonyms, and related words instantly from any application.

Keypirinha is a minimalist yet powerful portable launcher for Windows, designed for speed enthusiasts. It provides quick access to programs, files, and web searches through a streamlined interface, heavily relying on keyboard input for efficient navigation and workflow automation.

Multi Commander is a feature-rich, multi-tabbed file manager designed as a powerful alternative to standard Windows Explorer. It provides enhanced file management capabilities, extensive customization options, and supports a wide range of plugins and extensions.

Pinegrow Web Editor is a powerful desktop application for visually building websites and WordPress themes with live HTML and CSS editing. It combines the speed of a visual editor with the flexibility of a code editor, supporting popular frameworks like Bootstrap and Foundation.

Redaxscript is an exceptionally lightweight and high-performance Content Management System designed for simplicity and speed.

VMware vSphere Hypervisor, also known as ESXi, is a free, bare-metal hypervisor that allows users to virtualize their server hardware, consolidating applications and improving resource utilization. It provides a robust foundation for building virtualized IT environments.

PlantUML is an open-source tool that allows users to generate a wide variety of UML and other diagram types from a simple human-readable text description. It supports sequences, use case, class, activity, component, state, object, deployment, timing diagrams, and more, making it accessible and efficient for technical documentation and visualization.

Sleipnir is a versatile web browser designed for seamless integration between desktop and mobile devices. Offering a range of customization options, robust privacy features, and built-in tools like an RSS reader and social media integrations, Sleipnir aims to provide a tailored browsing experience.

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.

Nomacs is a fast and lightweight free, open-source image viewer offering a wide array of features for diverse image formats, including RAW and PSD. It provides essential editing tools, batch processing capabilities, and extensibility via plugins, making it more than just a simple viewer.

Fedena is an open-source school management software built on Ruby on Rails, designed to streamline administrative, academic, and communication processes for educational institutions.

Rocket.Chat is a comprehensive free and open-source team communication platform, offering real-time chat, audio/video conferencing, screen sharing, and file sharing. Designed for flexibility, it can be self-hosted on-premises for maximum control and customization, making it ideal for organizations prioritizing data privacy and security.

Programmer's Notepad is a fast and lightweight text editor designed specifically for programmers and developers. It offers extensive syntax highlighting for numerous programming languages, a powerful search and replace engine with regular expression support, and a highly customizable environment. Ideal for those seeking a free, open-source, and portable code editing solution.

dBpoweramp is a highly regarded audio software suite known for its robust CD ripping, audio conversion, and tag editing capabilities. It supports a wide range of audio formats and offers advanced features like AccurateRip verification and volume normalization for perfect audio quality.

EmEditor is a robust yet lightweight text editor for Windows designed for power users, developers, and anyone working with large files or needing advanced text manipulation features and it offers exceptional performance and customization.

Firefox Developer Edition is a specialized version of the Firefox browser tailored for web developers. It offers the latest features and tools earlier than the standard release, providing a stable yet cutting-edge environment for building and testing websites.

KDevelop is a powerful, free, and open-source Integrated Development Environment (IDE) designed for Unix-like systems, Windows, and macOS. It offers a robust set of features for a wide range of programming languages, including C++, Python, PHP, and more, making it a versatile tool for software developers.

GNU IceCat is a free software version of the Firefox web browser, distributed by the GNU Project. It focuses on user freedom and privacy by removing proprietary components and incorporating privacy-enhancing features.

Google Desktop was a powerful desktop search application designed to index and rapidly locate information across your computer. It integrated seamlessly with your operating system, offering indexed search for files, emails, web history, and more, along with a customizable sidebar for widgets and gadgets.

Wox is a highly customizable and extensible open-source application launcher for Windows. It allows users to quickly launch applications, search files, perform web searches, and execute commands using a simple keyword-based interface.

Claws Mail is a powerful yet lightweight, open-source email and news client built on GTK+. It's known for its speed, stability, rich feature set, and high degree of customization, making it an excellent choice for users demanding control and efficiency.

Mantis Bug Tracker is a free and open-source, web-based issue tracking system designed primarily for software defect tracking. It offers a straightforward interface and a range of features suitable for managing projects and tracking the lifecycle of bugs and issues.