Which regex flavor does it use?

The tool uses JavaScript's built-in RegExp engine, which supports most standard regex features including lookahead, lookbehind (in modern browsers), and named groups.

What are capture groups?

Capture groups are portions of a regex enclosed in parentheses (). They extract specific parts of a match. The tool displays each group's value separately.

Can I test with flags like global and case-insensitive?

Yes. You can toggle flags (g, i, m, s) to control matching behavior: global (all matches), case-insensitive, multiline, and dotAll.

Does it include common patterns?

Yes. A pattern library provides one-click access to common regex for emails, URLs, IP addresses, phone numbers, dates, and more.

Regex Tester

Test and debug regular expressions in real-time with match highlighting, capture groups, and common regex patterns.

regexregular expressionregex testerpattern matching

Common Use Cases

debugging small payloads and snippets
formatting code or data for readability
running fast checks without a full project setup

What is Regex Tester?

The Regex Tester lets you write and test regular expressions against sample text with real-time match highlighting, capture group extraction, and flag configuration (global, case-insensitive, multiline). It includes a library of common regex patterns for emails, URLs, phone numbers, and more, making it a go-to tool for developers learning or debugging regex.

How to Use This Tool

1Enter your regular expression pattern
2Type or paste test text in the input area
3See matches highlighted with capture group details

Example

Input

Pattern: (\d{3})-(\d{4}) | Text: Call 555-1234

Output

Match: 555-1234 | Groups: 555, 1234

Before You Rely on This Result

UtilityNest keeps this tool simple on purpose: the goal is to make the task easy to understand, fast to complete, and straightforward to double-check.

Review the inputs once more before you copy, save, or share the result.
Use the example and FAQ on this page to sense-check how the tool behaves.
When the result matters, compare one more scenario or related tool before acting on it.

Frequently Asked Questions

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