How do I test a regex pattern online?

Enter your regex pattern in the pattern field and your test text in the text area. The tool will highlight matches in real-time and show match details. You can toggle flags like case-insensitive (i), global (g), and multiline (m).

What are regex flags?

Regex flags modify pattern matching behavior: 'g' (global) finds all matches, 'i' (case-insensitive) ignores case, 'm' (multiline) treats ^ and $ as line boundaries, 's' (dotall) makes . match newlines, 'u' (unicode) enables unicode support.

How do I match email addresses with regex?

Use pattern: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} - This matches most email formats. For more strict validation, use: ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$

What does the 'g' flag do in regex?

The 'g' (global) flag makes regex find all matches in the text instead of stopping after the first match. Without 'g', only the first match is returned. With 'g', all occurrences are found.

Regex Tester - Test Regular Expressions Online Free

Regular Expression Pattern

g (global)

i (case-insensitive)

m (multiline)

Test Text

Common Regex Examples

\d{3}-\d{3}-\d{4}

Phone number (555-123-4567)

[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}

Email address

https?://[^\s]+

URL (http/https)

#[0-9A-Fa-f]{6}

Hex color code

\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b

IP address

Regex Tester

Test regular expressions online with real-time matching and highlighting. Our regex tester helps you validate patterns, debug regex, and learn regular expression syntax.

Regex Flags

g (global): Find all matches instead of stopping after first match
i (case-insensitive): Ignore case when matching (A = a)
m (multiline): ^ and $ match line boundaries, not just string boundaries

Common Regex Patterns

Digits: \d or [0-9]

Letters: [a-zA-Z]

Whitespace: \s

Word characters: \w (letters, digits, underscore)

Any character: .

Start of string: ^

End of string: $

Quantifiers

* - 0 or more times
+ - 1 or more times
? - 0 or 1 time (optional)
{n} - Exactly n times
{n,} - n or more times
{n,m} - Between n and m times

Common Use Cases

Validating email addresses and phone numbers
Extracting URLs from text
Finding patterns in log files
Data validation in forms
Text search and replace
Parsing structured data

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