Regex Tester
Test a regex pattern against any text and instantly see matches highlighted. Supports flags (g/i/m/s/u) and match details.
Matches
How to use
- 1
Enter a pattern
Type your regex and choose flags (g/i/m/s/u).
- 2
Enter test text
Type or paste the string you want to match against.
- 3
Check the results
Matches are highlighted and listed instantly.
Features
- Real-time matching as you type
- Supports flag combinations (g/i/m/s/u)
- Highlights matches and lists all matched strings
- Your input is never sent to a server
Use cases
Debug patterns
Check whether your regex-in-progress matches correctly against test strings.
Extract and validate data
Test regex used to extract or validate patterns in logs and data.
Compare flags
See the effect of flags like g (all matches) and i (case-insensitive).
Details
Regular expressions (regex) are a notation for describing string patterns - checking email formats, extracting substrings, and so on. They are used heavily in development and data processing.
This tool runs on the browser standard JavaScript RegExp, so no additional libraries are needed. You can combine flags (g=all matches, i=case-insensitive, m=multiline, s=dotall, u=Unicode) for testing.
If the pattern has an error, an error message is shown immediately. A list of matched strings is also displayed, which helps you debug patterns. Nothing you enter is sent to a server.
FAQ
Which regex engine is used?
The browser standard JavaScript RegExp. No additional libraries are required.
Which flags can I use?
You can combine g (all matches), i (case-insensitive), m (multiline), s (dotall), and u (Unicode mode).
Is my regex saved anywhere?
No. Everything is processed in your browser and nothing is stored or transmitted.
What should I do when a pattern error appears?
The regex has a syntax error. Check for unbalanced parentheses or missing escape characters (\).
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All processing happens in your browser. Your files are never uploaded.