- regex101 Online regex tester for PHP, PCRE, JavaScript and Python that highlights pattern and matches on the fly. Also features a Code generator and a regex debugger!
https://regexr.com/ Online regex tester with gut regex replace and explain functionality.
https://www.debuggex.com/ Can show neat expression diagrams (not active anymore).
https://regexper.com/ translates regular expressions into an SVG image (for documentation or embedding)
- RexV2 Evaluator for PHP PCRE, PHP Posix!, Perl, Python, Javascript, Node.JS!
- https://myregextester.com/index.php Allows to optimize patterns (I guess this is based on this Perl's Regexp::Optimizer).