Regex Vis

Regex Vis is a modern web application for visualizing regular expressions as interactive railroad diagrams. Users type a regular expression pattern into the editor and the tool renders the corresponding state-machine visualization in real time, showing how different parts of the pattern connect and flow. The visual display uses railroad diagram conventions familiar from formal language theory, with horizontal paths representing concatenation, branching for alternation, loops for quantifiers, and labeled states for capture groups, lookaheads, and lookbehinds. While the application requires JavaScript to run, it processes everything in the browser without sending data to a server. For developers learning regex syntax or debugging complex patterns with multiple groups and nested quantifiers, the graphical representation significantly reduces the cognitive load compared to reading raw patterns.