Regulex

Regulex is an open-source JavaScript regular expression visualizer created by developer Jex. It parses a JavaScript regular expression and renders it as a deterministic finite automaton state-machine diagram, giving developers a graphical representation of exactly how the regex engine processes input strings. The visualization shows every character group, quantifier loop, alternation branch, capturing group, and assertion in a clear railroad-diagram style that makes complex regex patterns substantially easier to understand. Users can enable or disable the ignoreCase, multiline, and globalMatch flags to see how they affect the matching graph. The rendered diagram can be exported as a PNG image or embedded into other websites via an iframe, making it useful for documentation, tutorials, and blog posts explaining regex behavior. For frontend developers debugging complex JavaScript regex patterns and for anyone learning how regular expressions work at the automaton level, Regulex turns opaque character sequences into readable visual flowcharts that reveal the underlying matching logic.