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Interactive Regex Tester

Developer

Test and debug regular expressions with live match highlighting.

ttb run regex-tester
//g
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How to Use Regex Tester

Enter your regular expression pattern in the top input field and your test string below it. The tool highlights all matches in real-time, shows capture groups, and displays match details. Toggle flags like global (g), case-insensitive (i), and multiline (m) to modify matching behavior. Use this to build, debug, and validate regex patterns before deploying them in your code.

1

Enter your parameters

Configure the inputs for the Regex Tester according to your specific needs.

2

View real-time results

The utility instantly processes your request and displays the calculated outputs directly in your browser.

3

Copy or Download

Click the copy icon next to the final output to instantly grab the result, or export it if applicable.

Frequently Asked Questions

What is a regular expression (regex)?+
A regular expression is a pattern-matching syntax used in programming to find, validate, or manipulate text. For example, the pattern \d{3}-\d{4} matches phone number formats like 555-1234.
Which regex flavor does this use?+
This tool uses JavaScript's built-in regex engine, which follows the ECMAScript specification. It supports most standard regex features including lookaheads, lookbehinds (in modern browsers), and named groups.
Why isn't my regex matching?+
Common issues include forgetting to escape special characters (like . or *), not enabling the global (g) flag for multiple matches, or not accounting for line endings in multiline text.
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