Browser tool
Regex Tester & Debugger
Test & debug regular expressions instantly with live matching and highlighting. Free online regex tool for developers. Real-time pattern testing with flag support. Secure, fast, no registration. Master regex patterns instantly. Start testing now!
Regular Expression Tester
Test a JavaScript regular expression against sample text in the browser. The page highlights matches. It does not explain each token.
Common Use Cases
- •Validating email addresses and phone numbers
- •Extracting data from log files and text documents
- •Searching and replacing text patterns in code
- •Validating user input in web forms
- •Parsing structured data from unstructured text
Who Benefits from This Tool
- •Software developers implementing data validation
- •Data analysts processing text data
- •DevOps engineers parsing log files
- •Web developers creating form validation
- •System administrators managing text processing
Frequently Asked Questions
What regex flavors are supported?
The tester uses JavaScript RegExp only. Flags can combine g, i, m, s, u, and y. The same pattern can behave differently in Python, Java, or C#.
Can I test regex with multiple test strings?
The page has one sample box. Paste the text you want to test in that box.
Does the tool explain regex patterns?
No. It shows the matches and refuses patterns that are too long or use nested quantifiers. It does not describe each token.
Is there a limit on regex pattern length?
Yes. Patterns longer than 500 characters and samples longer than 20,000 characters are refused, as are nested quantifiers.
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