Notepad3 is a lightweight Windows text editor designed as a replacement for the default system notepad. It is built on the Scintilla text engine to provide source code editing capabilities, including syntax highlighting, code folding, and automatic indentation.
The editor is distinguished by its support for registry-free portable execution, allowing the application to run from removable storage without system installation. It features integrated file encryption and decryption tools for secure document management and a regular expression engine for complex search and replace operations across files.
The application covers a broad range of text manipulation utilities, including character encoding conversion, rectangular selection, and word auto-completion. It also includes functional tools such as an inline mathematical expression evaluator, a clipboard data collection utility, and an event-driven file monitoring system that automatically reloads documents when changes are detected on disk.
The user interface supports localization into multiple languages and is customizable via themed color schemes, dark mode, and configurable keyboard shortcuts.
