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Regex Tester
Test regular expressions against sample text, inspect matches, and review capture groups with live highlighting.
regex testerregex checkerregular expression testerregex validator
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Highlighted matches
0 matchesRun a regex to see highlighted matches here.
Capture groups
Per matchHow to use
How to test regular expressions and inspect matches with confidence
- 1 Enter the regular expression pattern you want to test into the pattern field at the top of the page.
- 2 Turn on the flags you need, such as global matching, case-insensitive search, multiline mode, or dotAll behavior.
- 3 Paste your sample text into the test string area so the tool has real content to evaluate against the pattern.
- 4 Click Test regex to highlight matches, count the number of hits, and reveal capture groups for each match.
- 5 Adjust the pattern or flags until the highlighted output and capture group table match the behavior you expect.
Regular expressions are powerful, but even experienced developers can lose time when a pattern behaves differently than expected. Small changes in flags, quantifiers, anchors, or capture groups can produce a very different result, especially across large blocks of text. A regex tester helps by putting the pattern, flags, sample text, highlighted matches, and group breakdown on one page. That makes it much easier to debug searches, validation rules, parsing logic, and text transformations before you move a pattern into production code.
The capture group table is especially helpful when you are building extractors, route matchers, input validators, or replacement rules that depend on specific submatches. Seeing the full match alongside each captured group reduces guesswork and makes edge cases easier to spot. Because everything runs directly in the browser with standard JavaScript regular expressions, the output reflects the same core regex behavior you will use in many front-end and Node.js workflows.
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