Regex Tester
Test regular expressions against sample text with live match highlighting and a cheatsheet.
Free, no signup needed. Runs 100% in your browser.
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How to use this tool
- Type your pattern and flags.
- Add sample text.
- See matches highlight live.
Frequently asked questions
Which regex flavor?
JavaScript RegExp, the same engine your browser uses.
Why did my pattern fail?
Common causes are unescaped dots, greedy quantifiers, and missing flags like global or case-insensitive.
Why does a complex pattern freeze the page?
Nested quantifiers can cause runaway backtracking. Simplify the pattern or anchor it to limit how many ways the engine tries.
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