Open-source alternatives to Notepad3

Macdown is a markdown text editor and HTML renderer designed for structured document composition. It provides a workspace for writing in lightweight markup syntax while simultaneously generating a live HTML preview of the rendered output. The editor distinguishes itself through a programmable interface, offering a command line utility to open files or pipe text directly into the application. It further supports extensibility via a plugin system that allows for the addition of custom features and functional modules at runtime. The application handles technical documentation requirements inclu

Atom is an extensible code IDE and hackable text editor designed for source code editing and the creation of custom development environments. It functions as a syntax highlighting editor and a version control integrated editor that tracks file changes and synchronizes code with remote repositories. The editor allows for the modification of its own core functionality and supports a package-based plugin system for creating custom themes and snippets. It also serves as a Markdown preview editor, providing side-by-side visual rendering for content authoring. The platform includes capabilities fo

This project is a comprehensive, community-maintained knowledge base and toolkit designed for competitive programming. It serves as a centralized repository for algorithmic theory, data structures, and mathematical techniques, providing a structured reference for informatics and collegiate programming competitions. The project distinguishes itself by integrating educational content with a robust suite of automation utilities. It provides a complete workflow for competitive programming, including tools for automated test case generation, solution verification, and direct interaction with onlin

Vditor is a browser-based Markdown editor and rendering engine that supports multiple editing interfaces, including a visual rich-text experience, instant rendering, and a traditional side-by-side split-view preview. It serves as an authoring tool for technical documentation and a component for web-based editor integration. The project is distinguished by its support for complex technical content, utilizing specialized rendering for mathematical formulas, flowcharts, sequence diagrams, and mind maps. It also functions as a collaborative document review tool, enabling users to attach anchored

TagSpaces is an offline-first file tagging and organization platform that lets you manage local files with portable metadata stored directly in filenames or sidecar JSON files, eliminating the need for a central database. It functions as a full-text file search engine, a Kanban board file organizer, a local AI file assistant, an S3-compatible cloud file manager, and a web clipper and bookmark manager, all within a single application. The project distinguishes itself through a local-first architecture where all file operations, indexing, and AI processing run entirely on the device, with cloud

This project is a desktop screen capture and annotation utility designed for Linux environments. It provides an interactive graphical overlay that allows users to select specific screen regions, apply visual annotations such as shapes, text, and pixelation, and manage the resulting images through a configurable post-capture pipeline. The application distinguishes itself through deep system integration and automation capabilities. It operates as a persistent background daemon that monitors global hotkeys and supports inter-process communication via a system message bus, enabling users to trigg

notepad-- is a cross-platform plain text editor designed for creating and modifying unstructured text files. It functions as a lightweight productivity tool that allows users to write and save documents across Windows, Linux, and macOS. The application utilizes a buffer-based editing model to decouple file storage from the visual display. This approach enables a consistent user interface for local file management and plain text document creation regardless of the underlying operating system.

Apkstudio is a reverse engineering integrated development environment designed for decompiling, modifying, and recompiling Android application packages. It provides a specialized suite for transforming binary files into readable source code and bundling them back into installable application archives. The project features a framework integration system that imports manufacturer-specific files to ensure accurate decompilation of vendor-modified applications. It includes a dedicated editor for Smali, Java, and XML files with syntax highlighting, as well as a hex editor for the direct modificati

Notepad++ is a high-performance, lightweight source code editor designed for local development on Windows. Built as a native desktop application, it utilizes a specialized editing component to manage text buffers and render syntax highlighting for large files with minimal resource overhead. The editor distinguishes itself through a robust plugin architecture that allows users to extend core functionality by loading external binary modules at runtime. It also provides extensive support for custom language definitions, enabling users to map unique syntax rules and keywords to the rendering engi

CodeEdit is an open-source integrated development environment and native macOS code editor. It provides a workspace for writing and modifying source code, combining a text editor with project management tools. The editor is built specifically for macOS using native frameworks to ensure performance. It features a plugin system that allows for the addition of specialized features and custom logic to extend the editing experience. The environment includes an integrated terminal emulator for executing development commands and debugging tools. It also provides project-wide file indexing for globa

Pulsar is a cross-platform, extensible text editor designed for source code management and plain text editing. It functions as a plugin-based development environment that allows for the creation of a personalized workspace through deep configuration of language settings, visual styles, and keyboard shortcuts. The editor is characterized by its extensibility, supporting the integration of third-party extension packages to add specialized features and custom toolsets. Users can modify the interface via visual theme customization and build tailored workflows using a framework for custom developm

LightTable is an extensible source code editor and integrated development environment designed as an interactive programming environment. It enables the evaluation of programming language fragments in real time to provide instant feedback on expressions. The workspace functions as a remote execution environment, connecting to and managing external servers to run code within remote processes. It allows for an interactive workflow where users can execute code fragments and track expression values without restarting the environment. The system provides source code editing capabilities, includin

LiteIDE is a cross-platform integrated development environment designed for writing, compiling, and debugging Go source code. It functions as both a code editor with syntax highlighting and a build tool orchestrator that manages toolchains, environment profiles, and cross-compilation targets. The environment is modular and extensible, supporting third-party plugins and custom keyboard mapping to tailor the coding workflow. It provides an integrated interface for external debuggers to inspect program execution and state. The platform covers a broad range of development capabilities, including

OpenInTerminal is a system interface extension for macOS that provides a custom Finder context menu, toolbar extensions, and clipboard utilities. It functions as a terminal emulator launcher and a shell path utility, allowing users to interact with the macOS file system through external applications. The project enables the launch of terminals and text editors directly from the file manager. It includes a shell path utility to copy escaped file paths to the clipboard and supports the configuration of specific terminal emulators and code editors. The software covers workflow automation throug

Vim is a keyboard-driven text editor designed for the high-speed manipulation of source code and plain text files. It utilizes a modal interface that interprets keystrokes as either text insertion or complex navigation and editing commands. Built on a portable C core, the software maintains a consistent experience across diverse operating systems and terminal emulators through an abstraction layer that manages text in memory-mapped buffers. The editor functions as a highly modular platform that supports extensive customization through a built-in scripting engine and a plugin-based architectur

Micro is an extensible terminal text editor that supports mouse interaction and intuitive keyboard shortcuts for editing files in a command line environment. It functions as a multi-cursor editor with syntax highlighting and a plugin system for adding custom functionality and automation scripts. The editor distinguishes itself through simultaneous editing across multiple cursors and a script-based extension system. It enables the automation of repetitive editing tasks via macro recording and playback of keystroke sequences. The project covers workspace management through split-screen panes a

fsnotes is a markdown notes manager and cross-platform markdown editor for macOS and iOS. It functions as a personal knowledge base that organizes plain text and markdown files across folders using tags and bidirectional links. The system provides a secure environment through an encrypted plain text notebook that protects individual notes and folders. It implements Git-based note versioning to track document changes and maintain backups, while relying on external cloud storage services to synchronize files across devices. The application renders mathematical formulas, diagrams, and syntax-hi

unioffice is a comprehensive document processing suite that provides a PDF document processor, an Open XML document library, a document security toolkit, and a document content extractor. It is designed to programmatically create, read, and modify Word, Excel, and PowerPoint files, as well as generate and edit PDF documents. The project is distinguished by its native language implementation of the Open XML standard, which removes native binary dependencies to simplify container deployments. It features advanced capabilities for digital document security, including hardware-based PDF signing,

Brackets is an extensible JavaScript IDE and front-end code editor specifically designed for authoring HTML, CSS, and JavaScript. It serves as a web development text editor that provides a specialized environment for building websites. The editor is distinguished by its live preview capabilities, which render code changes in a browser in real time for immediate visual feedback. It further supports front-end workflows through inline style editing and the ability to synchronize code changes across multiple browser windows for cross-browser testing. The project includes a wide range of developm

CotEditor is a native macOS plain text editor designed for lightweight file modification and developer use. It is a desktop application built specifically for the macOS operating system to ensure high performance and system integration. The project functions as a text encoding manager, providing the ability to process and convert a wide range of plain text formats and legacy character encodings to prevent corruption and display errors. Its capabilities cover plain text editing, lightweight code editing for scripts and configuration files, and general macOS text processing.

This project is a comprehensive productivity guide and configuration reference for the VS Code editor. It provides a curated collection of shortcuts, configuration tips, and tutorials designed to improve efficiency and optimize the daily coding workflow. The resource covers advanced AI-assisted development, including the integration of autonomous agents, custom prompt files, and AI-powered coding assistants for task automation and code generation. It also provides specialized guidance on integrated terminal management, such as configuring shell profiles and automating command execution. Addi

Kit is a desktop automation framework and scriptable UI toolkit designed for building personalized productivity tools. It serves as a cross-platform CLI wrapper and macOS system automator, providing an environment to execute scripts that manage operating system tasks, file management, and application workflows. The project distinguishes itself with a dedicated LLM integration layer for structured data extraction and text generation, alongside a specialized UI framework for creating interactive input forms, HTML windows, and floating widgets. It features deep macOS integration through AppleScr

Zed is a terminal-based code editor built in Rust that provides a full-featured editing experience with familiar keybindings, mouse support, and multiple cursors. It runs entirely in the terminal while offering capabilities typically found in graphical editors, including split panes, a command palette, and integrated language server protocol support for real-time diagnostics, completions, go-to-definition, and code actions across multiple languages. The editor distinguishes itself through a plugin system that runs sandboxed TypeScript plugins in a QuickJS runtime, with an asynchronous bridge

MarkEdit is a high-performance Markdown text editor and document navigator. It provides a scriptable editing environment that supports side-by-side HTML rendering for real-time formatting previews. The editor is distinguished by a multi-caret engine that enables rectangular block selections and simultaneous modification of multiple text ranges. It allows for extensive interface and functional customization through external CSS stylesheets and the integration of system-level scripts to automate repetitive tasks. The application includes tools for managing large documents, such as content bloc

sd is a command line text manipulation utility designed for searching and replacing text patterns across multiple files. It functions as a regex-based find and replace tool that allows for in-place file editing directly from the terminal. The project supports both regular expression replacements, including the use of capture groups for complex transformations, and fixed string replacement for literal text substitutions. It specifically handles multi-line text replacement by processing file contents as single blocks to match patterns that span across newline characters. The tool provides capa

QOwnNotes is a desktop note editor that stores each note as a plain-text Markdown file on the local filesystem, avoiding proprietary formats and enabling direct file access. It functions as a Nextcloud Notes client, syncing notes and metadata with Nextcloud or ownCloud servers through a companion API service for versioning and sharing. The application also integrates with AI providers and exposes a local MCP server for external agents to search and fetch notes, and includes a companion browser extension for capturing web content, bookmarks, and screenshots. The editor distinguishes itself thr

bootstrap-fileinput is a Bootstrap-compatible HTML5 file upload widget and plugin. It provides a customizable interface for selecting and uploading multiple files, featuring integrated image previews, drag-and-drop support, and client-side validation for file types, sizes, and counts. The project includes a resumable file upload client that slices large files into chunks to ensure stability over intermittent connections and allow transfers to be paused and resumed. It also features a client-side image processor capable of resizing images and reading EXIF metadata to automatically correct imag