TiddlyWiki5 gains new capabilities through a [[completely rebuilt architecture|TiddlyWikiArchitecture]] using the latest features of HTML5 and node.js. It runs natively under node.js, and can also use its own components to construct a version of itself that works entirely within the browser, just as TiddlyWiki has always done.
TiddlyWiki5 also functions as the build system for earlier versions of TiddlyWiki, replacing the elderly Cook and Ginsu tools (see https://github.com/TiddlyWiki/cooker for details). See the CommandLineInterface for details.
Try out the prototype tiddler chooser by swiping into the left edge of the screen (or hover the mouse over the extreme left edge of the browser window).