Free Online Regex Tester
Test, validate, and debug regular expressions with real-time matching and detailed results.
Example Patterns
Choose from common regex patterns to test and learn
Regular Expression Pattern
Enter your regex pattern and select flags
Test String
Enter the text to test against the pattern
Matches
Found 0 matches
Regular Expression Flags
Understanding regex flags and their usage
Matches all occurrences of the pattern in a string, not just the first one
Pattern: cat
Text: cat and cat
With flag: Matches both 'cat's
Without flag: Only matches first 'cat'
Makes the pattern case-insensitive
Pattern: hello
Text: Hello HELLO hello
With flag: Matches all variations regardless of case
Without flag: Only matches exact 'hello'
^ and $ match the start/end of each line, not just the whole string
Pattern: ^start
Text: start start
With flag: Matches 'start' at beginning of each line
Without flag: Only matches 'start' at beginning of string
Dot (.) matches newline characters \n
Pattern: .*
Text: line1 line2
With flag: Matches entire text including newline
Without flag: Matches up to newline only
Enables Unicode support. Useful for non-ASCII characters and emoji
Pattern: \u{1F604}
Text: 😄 smile
With flag: Matches Unicode emoji
Without flag: No Unicode support
Matches only from the last index position
Pattern: \w+
Text: first second
With flag: Matches only from lastIndex
Without flag: Matches anywhere in string
Regex Cheatsheet
Quick reference for common regex patterns and usage
Character Classes
.Any character except newline
Example: a, b, c, 1, @, etc.
\wWord character
Example: a-z, A-Z, 0-9, _
\dDigit
Example: 0-9
\sWhitespace character
Example: space, tab, newline
\WNot a word character
Example: @, #, $, etc.
\DNot a digit
Example: anything except 0-9
\SNot a whitespace character
Example: any visible character
Quantifiers
*0 or more times
Example: ab* matches 'a', 'ab', 'abb', etc.
+1 or more times
Example: ab+ matches 'ab', 'abb', but not 'a'
?0 or 1 time
Example: ab? matches 'a' or 'ab'
{n}Exactly n times
Example: a{3} matches 'aaa'
{n,}n or more times
Example: a{2,} matches 'aa', 'aaa', etc.
{n,m}Between n and m times
Example: a{2,4} matches 'aa', 'aaa', 'aaaa'
Anchors
^Start of string/line
Example: ^hello matches 'hello world'
$End of string/line
Example: world$ matches 'hello world'
\bWord boundary
Example: \bcat\b matches 'cat' but not 'category'
\BNot a word boundary
Example: \Bcat\B matches 'category' but not 'cat'
Groups & Assertions
(abc)Capturing group
Example: (\w+)@(\w+\.\w+) captures username and domain
(?:abc)Non-capturing group
Example: (?:https?://) matches protocol without capturing
a(?=b)Positive lookahead
Example: a(?=b) matches 'a' only if followed by 'b'
a(?!b)Negative lookahead
Example: a(?!b) matches 'a' only if not followed by 'b'
Common Patterns
^[\w.-]+@([\w-]+\.)+[\w-]{2,}$Basic email validation
https?:\/\/[\w\d\-._~:/?#[\]@!$&'()*+,;=]+Basic URL validation
\+?\d{1,4}?[-.\s]?\(?\d{1,3}?\)?[-.\s]?\d{1,4}[-.\s]?\d{1,4}[-.\s]?\d{1,9}International phone number
^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[!@#$%^&*])[A-Za-z\d!@#$%^&*]{8,}$At least 8 characters, upper, lower, number, special
Features
Our Regex Tester tool provides comprehensive features for testing and debugging regular expressions.
Real-Time Testing
Test your regex patterns instantly with live highlighting of matches as you type.
Regex Flags Support
Use standard regex flags (g, i, m, s, u, y) to modify pattern matching behavior.
Match Details
View detailed information about matches, including indices and captured groups.
Easy Export
Copy or download match results for further analysis or documentation.
Match Navigation
Navigate through multiple matches easily with next/previous controls.
Syntax Validation
Instant feedback on regex syntax errors to help debug patterns.
How to Use the Regex Tester
Follow these easy steps to get started with Regex Tester and achieve your goals quickly.
Enter your regular expression pattern in the pattern field and select appropriate flags (g, i, m, etc.).
Type or paste your test text in the input area. Matches will be highlighted in real-time.
View match details, navigate through matches, and use copy/download options for results.
Frequently Asked Questions
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