Regex Tester Online Free
Test regular expressions online instantly. Enter a pattern, choose JavaScript flags, highlight matches and inspect captured groups directly in your browser.
Highlighted Text
Matches
How to Test a Regex
Check your regular expression pattern in three simple steps.
1. Enter pattern
Paste or type your regular expression without slash delimiters.
2. Add test text
Paste the text where you want to find matches.
3. Review matches
See highlighted matches, match count and captured groups.
Debug JavaScript regular expressions faster.
This Regex Tester helps developers validate patterns, inspect matches, test flags, find captured groups and debug text matching directly in the browser.
You can use common JavaScript regex flags, highlight all matches, inspect match indexes, review captured groups and copy matched results instantly.
What is a regex tester?
A regex tester lets you check a regular expression pattern against sample text and see exactly what it matches. It is useful for validating patterns before using them in code.
This tool uses JavaScript regular expressions because it runs directly in your browser.
When should you use it?
- Testing email, URL or phone patterns
- Debugging JavaScript regular expressions
- Checking captured groups and match indexes
- Trying regex flags such as g, i, m and u
- Finding and validating text patterns quickly
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Regex Tester FAQ
Common questions about testing regular expressions online.
What is a regex tester?
A regex tester helps you check a regular expression pattern against sample text and see what it matches.
Which regex flavor does this tool use?
This tool uses JavaScript regular expressions because it runs directly in your browser.
Can I test regex flags?
Yes. You can test common JavaScript flags such as g, i, m, s, u and y.
Is this Regex Tester free?
Yes. This online Regex Tester is free to use.
Should I include slash delimiters?
No. Enter only the pattern, without starting and ending slash delimiters.
Can I inspect captured groups?
Yes. The tool shows captured groups for each match when your pattern includes groups.
Does this tool upload my text?
No. Your pattern and test text are processed directly in your browser.
Why are flags important?
Flags change how regex matching works, such as global matching, case-insensitive matching and multiline matching.