Regex Tester
Checked and verified · August 15, 2026
Test a regular expression against sample text and see every match, capture group, and replacement highlighted live. Runs entirely in your browser — nothing is uploaded.
Flags
Mode
Matches & capture groups
Result
For any feedback, bug report and request:
Contact UsHow it works
- Type or paste your regular expression pattern and choose its flags (global, case-insensitive, multiline).
- Paste sample text below — matches are highlighted live as you type either field.
- Switch to the Replace tab to preview what a replacement string would produce.
- Each match's captured groups are listed below the text with their positions.
Frequently asked questions
Does this send my pattern or text anywhere?
No — matching runs entirely in your browser using JavaScript's built-in regex engine. Nothing is uploaded.
What flavor of regex does this use?
JavaScript (ECMAScript) regex syntax — the same engine used by browsers and Node.js. It's very close to PCRE/Python syntax for most everyday patterns, but a few advanced features differ, so double-check anything highly specialized against your actual target language.
What happens with an invalid pattern?
A clear error message explains what's wrong (like an unclosed group or bracket) instead of silently matching nothing.
Can I test replacements, not just matches?
Yes — the Replace tab lets you enter a replacement string, including capture group references like $1, and shows the resulting text live.
Is there a risk of the page freezing on a bad pattern?
Certain "catastrophic backtracking" patterns can be slow in any regex engine, including this one — if a match seems to hang, simplify the pattern or shorten the test text.
Your files are never uploaded. Gotool.xyz runs entirely as JavaScript in your browser. Your files are processed in memory and never touch a server — nothing to breach, nothing to clean up. Close the tab and it's like it never happened. The only thing we count is which tool ran (just the name, e.g. "merge") so we know what people find useful — never your file, its name, its size, or anything in it.
