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Regex Tester

📁Developer Tools
💳1 credit per use
🔄Updated March 13, 2026

Test and debug regular expressions in real time. See matches highlighted instantly, view capture groups, get explanations of your pattern, and test against multiple strings.

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Overview

Regular expressions are incredibly powerful but notoriously difficult to get right. The Regex Tester gives you a live testing environment where you can write, test, and debug regex patterns with instant visual feedback on matches.

Type your regex pattern in the top field and your test string below. Matches are highlighted in real time as you type, with different colors for capture groups so you can see exactly what each part of your pattern is matching. No more running your code, checking output, tweaking, and running again.

The built-in regex explainer breaks down your pattern into plain English. Hover over any part of the expression to see what it does. This is invaluable for learning regex or understanding patterns written by others. The tool also includes a library of common patterns for emails, URLs, phone numbers, dates, and more.

Key Features

Live Match Highlighting
See matches highlighted in real time as you type your pattern and test string, with unique colors for each capture group.
Pattern Explainer
Get a plain-English explanation of what your regex pattern does, broken down token by token.
Multi-Flavor Support
Test patterns against JavaScript, Python, PHP, Java, and Go regex engines since flavors differ in feature support.
Common Patterns Library
Access a library of pre-built patterns for emails, URLs, IP addresses, dates, phone numbers, and other common validations.
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How to Use Regex Tester

Enter Your Pattern
Type your regular expression in the pattern field. Set flags like global, case-insensitive, and multiline as needed.
Add Test Strings
Enter one or more test strings to match against. Each match is highlighted in real time.
Review Matches
See all matches, capture groups, and their positions in the test string clearly highlighted.
Refine and Export
Adjust your pattern until it matches correctly, then copy the regex for use in your code.

Frequently Asked Questions

Which regex flavors are supported?
The tool supports JavaScript (ECMAScript), Python, PHP (PCRE), Java, and Go regex flavors. Each has slight differences in feature support.
Can I test multi-line patterns?
Yes. Enable the multiline flag to test patterns across line boundaries. The dotall flag allows the dot to match newline characters as well.
What are capture groups?
Capture groups are portions of your pattern enclosed in parentheses. They isolate specific parts of a match for extraction. The tester highlights each group in a different color.
Can I save my patterns?
Pro subscribers can save patterns to a personal library for quick access later. Free users can copy or bookmark patterns.
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