Regex Tester & Builder
Test and build regular expressions with real-time pattern matching, visual helpers, and code generation.
Code Generation
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What are Regular Expressions?
Regular expressions (regex) are powerful patterns used for matching, searching, and manipulating text. They're essential tools for developers, data analysts, and anyone working with text processing.
How to Use This Regex Tester
- Enter your regex pattern in the pattern field
- Add test strings to see real-time matches
- Use flags to modify pattern behavior (global, case-insensitive, multiline)
- View matches highlighted in your test text
- Generate code for your favorite programming language
Common Regex Patterns
- Email:
^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$ - Phone (US):
^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$ - URL:
https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*) - IPv4:
^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$ - Date (MM/DD/YYYY):
^(0[1-9]|1[0-2])\/(0[1-9]|[12][0-9]|3[01])\/\d{4}$
Regex Quick Reference
| Pattern | Description | Example |
|---|---|---|
. | Any single character | a.c matches "abc", "a1c" |
* | Zero or more | ab* matches "a", "ab", "abbb" |
+ | One or more | ab+ matches "ab", "abbb" |
? | Zero or one | colou?r matches "color", "colour" |
[abc] | Character class | [aeiou] matches any vowel |
^ | Start of line | ^Hello matches "Hello world" |
$ | End of line | world$ matches "Hello world" |
\d | Any digit | \d{3} matches "123" |
\w | Word character | \w+ matches "hello123" |
\s | Whitespace | a\s+b matches "a b" |
Frequently Asked Questions
What regex flavors does this tester support?
Our regex tester uses JavaScript regex engine, which supports PCRE-style patterns with ECMAScript extensions.
Can I save my regex patterns?
You can copy the generated code or bookmark the page with your pattern. All processing happens in your browser for privacy.
How do I use regex flags?
Click the flag buttons to enable: g (global - find all matches), i (case-insensitive), m (multiline - ^ and $ match line breaks).
Is this regex tester free?
Yes, completely free with no limits. No signup or payment required.
Can I test regex for different programming languages?
The tester uses JavaScript regex, but we provide code generation for multiple languages including Python, Java, PHP, and more.