Regex Tester
Test regular expressions with live match highlighting and replacement. Everything runs in your browser, so your input isn’t uploaded.
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How to use the Regex Tester
- Enter a pattern and choose flags such as g (all matches) or i (ignore case).
- Type or paste the text to search, or select Load sample.
- Read the highlighted matches and groups. Optionally enter a replacement to preview the result.
Example
The pattern finds an address and captures the part before and after the @ sign. With the g flag, every match is listed with its position and groups.
Pattern: (\w+)@(\w+)\.com Text: mail ada@site.com or bob@corp.com
Match 1 at 5: ada@site.com (groups: ada, site) Match 2 at 21: bob@corp.com (groups: bob, corp)
About this tool
A regular expression is a compact pattern for finding text. Type a pattern and some test text, and every match is highlighted immediately, with its position and capture groups listed below. You can also preview a replacement.
Good to know
- This uses JavaScript’s regular expression engine. Other languages can behave differently.
- Some patterns can be extremely slow on certain text and may freeze this tab for a while. Test text is limited to 200,000 characters and matches to 1,000.
- In a replacement, $1 is the first group, $& is the whole match, and $$ is a literal dollar sign.
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