Free Tools /Development
Regex Tester for Automation
Test a regular expression against real sample text, see every match and capture group highlighted live, and get a plain-English breakdown of the pattern.
- Free, no signup
- Runs in your browser
- Nothing stored
Matches & capture groups
How this tool works
Live matching against real text
Type a pattern and sample text, matches highlight instantly as you type, using your browser's native JavaScript regex engine, the same one n8n's Code and Set nodes run on.
Capture group breakdown
Every capture group in a match is listed separately, useful for confirming exactly what a Set node expression or a Code node's match.groups will actually extract.
Plain-English pattern breakdown
Common regex syntax (anchors, character classes, quantifiers, groups) in your pattern is decoded into a short description, so you do not need to remember what \d+? means at a glance.
Frequently asked questions
Does this use the same regex engine as n8n?
Yes. n8n's Code node and expression fields run on Node.js, which uses the same JavaScript regex engine as your browser. A pattern that matches here will behave identically inside an n8n Code node.
Why is my pattern not matching anything?
The most common causes are: forgetting the "g" flag when you expect multiple matches, using a capture group syntax not supported without a flag (like named groups needing correct (?
What is the difference between .* and .*? (greedy vs lazy)?
By default, quantifiers are greedy: .* matches as much text as possible, then backtracks if needed. Adding a "?" makes it lazy: .*? matches as little as possible. This matters most when your pattern has multiple similar delimiters in the sample text, greedy vs lazy can produce very different match boundaries.
Can this tool test multiline text?
Yes, paste multiline sample text directly. Add the "m" flag if you need ^ and $ to match the start and end of each line rather than only the start and end of the entire string.
Does this tool store my pattern or sample text?
No, everything runs client-side in your browser. Nothing is transmitted or saved.
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