Stack Online Tools is a comprehensive, browser-based toolbox offering more than 100 free utilities for developers, designers, marketers and content creators. Organized by category — including text tools (case converter, word counter, diff checker), encoding & security (Base64, hashes, QR codes), data/JSON tools, code/dev utilities (formatters, minifiers, regex tester), SEO & marketing items (meta-tag generator, URL slug tool), image/media tools and more.