About this tool
This is a full regular-expression workbench in the spirit of regex101, but 100% client-side: your pattern and test text never leave the browser, and the "shareable link" encodes everything into the URL itself rather than saving it on a server. It uses the browser's native JavaScript (ECMAScript) regex engine, so what you see here behaves exactly as it will in your JS/TypeScript code and in Node. As you type, matches are highlighted live in the test string, the Matches panel breaks out every capture group (numbered and named) with its position, Substitution previews a replacement (with $1, $<name>, $&), the Explanation panel describes the pattern token by token, and Code generates a ready-to-paste snippet for seven languages. It's built for engineers writing validation, log parsing, routing rules or data extraction who want to get a tricky expression right before it ships.
Frequently asked questions
Which regex flavor does it use?
JavaScript / ECMAScript, the engine built into your browser. That makes it exact for JS, TypeScript and Node. The generated code for other languages maps the pattern and flags across, but be aware some advanced constructs (e.g. lookbehind, named-group syntax) differ slightly between flavors.
Is the shareable link private?
Yes. Unlike server-backed regex sites, the link encodes your expression, flags and test string into the URL fragment (after the #), which is never sent to our server. Anyone with the link can open the same workbench; no account or database is involved.
Will it hang on a "catastrophic" regex?
A pathological pattern on a large input can make any backtracking engine slow. This tool guards zero-length matches and caps iterations, and shows the match time so you can spot a slow expression, but if the page briefly freezes on a very evil pattern, simplify it and try again.
Is anything uploaded?
No. Matching, substitution, explanation and code generation all run locally in your browser.