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Regex Tester & Builder

Build, test, and debug regular expressions with real-time match highlighting, capture groups, replace preview, and a library of common patterns.

regexRegular Expression

//g

text_fieldsTest String

1
1

targetMatch Results

Total Matches
0
Groups per Match
0
Flags
g
Enter a pattern and test string to see results

find_replaceFind & Replace

library_booksCommon Regex Patterns

How to Test Regex Online

edit

1. Enter Your Pattern

Type or paste your regular expression into the regex input field. Toggle flags like global, case-insensitive, or multiline to modify matching behavior.

text_fields

2. Add Test String

Paste the text you want to test against. Matches are highlighted in real time so you can see exactly what your pattern captures.

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3. Review Results

See all matches, their positions, and captured groups. Use the replace feature to preview substitutions, or copy results to your clipboard.

Regex Cheat Sheet

Character Classes

.Any character except newline
\dDigit (0-9)
\DNon-digit
\wWord character (a-z, A-Z, 0-9, _)
\WNon-word character
\sWhitespace (space, tab, newline)
\SNon-whitespace
[abc]Any of a, b, or c
[^abc]Not a, b, or c
[a-z]Character range a to z

Quantifiers & Anchors

*Zero or more
+One or more
?Zero or one (optional)
{n}Exactly n times
{n,m}Between n and m times
^Start of string / line
$End of string / line
\bWord boundary
(abc)Capturing group
a|bAlternation (a or b)

Common Regex Patterns

mail

Email Regex Pattern

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

Match email addresses. Click the quick-insert button above to test it instantly with your own data.

link

URL Regex Pattern

https?:\/\/[\w\-._~:/?#\[\]@!$&'()*+,;=%]+

Match HTTP/HTTPS URLs. Click the quick-insert button above to test it instantly with your own data.

phone

Phone Regex Pattern

\+?\d{1,4}[\s\-]?\(?\d{1,4}\)?[\s\-]?\d{1,4}[\s\-]?\d{1,9}

Match phone numbers (international). Click the quick-insert button above to test it instantly with your own data.

router

IP Address Regex Pattern

\b(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\b

Match IPv4 addresses. Click the quick-insert button above to test it instantly with your own data.

calendar_month

Date Regex Pattern

\b\d{4}[\-/]\d{2}[\-/]\d{2}\b|\b\d{2}[\-/]\d{2}[\-/]\d{4}\b

Match dates (YYYY-MM-DD or MM/DD/YYYY). Click the quick-insert button above to test it instantly with your own data.

code

HTML Tag Regex Pattern

<\/?[a-zA-Z][a-zA-Z0-9]*(?:\s[^>]*)?\/?>

Match HTML tags. Click the quick-insert button above to test it instantly with your own data.

tag

Number Regex Pattern

-?\d+(?:\.\d+)?

Match integers and decimals. Click the quick-insert button above to test it instantly with your own data.

Frequently Asked Questions

What is a regular expression (regex)?expand_more
A regular expression is a sequence of characters that defines a search pattern. It is used for pattern matching within strings, allowing you to find, validate, extract, and replace text. Regex is supported in virtually every programming language including JavaScript, Python, Java, PHP, and more.
How do I test a regex pattern?expand_more
Enter your regex pattern in the input field at the top of this page, then paste your test string in the textarea below. Matches are highlighted in real time. You can toggle flags (global, case-insensitive, multiline, dotall, unicode) to change matching behavior, and view detailed match information including positions and captured groups.
What do regex flags do?expand_more
Flags modify how the regex engine matches patterns. "g" (global) finds all matches instead of stopping at the first. "i" (case-insensitive) ignores letter casing. "m" (multiline) makes ^ and $ match line boundaries. "s" (dotall) makes the dot match newlines. "u" (unicode) enables full Unicode matching support.
What are capturing groups in regex?expand_more
Capturing groups are defined with parentheses ( ) in your pattern. They capture the matched text within the group, which you can reference in replacements using $1, $2, etc. For example, the pattern (\d{4})-(\d{2})-(\d{2}) matches dates and captures year, month, and day separately.
How do I use find and replace with regex?expand_more
Enter your regex pattern, paste your test string, then type your replacement string in the Replace field. Use $1, $2, etc. to reference captured groups. The replacement preview updates in real time so you can verify the result before copying it.
Is this regex tester free to use?expand_more
Yes, Vynoe Regex Tester is completely free with no signup required. All processing happens directly in your browser, so your data never leaves your device. There are no limits on pattern complexity or test string length.
Does this tool support all regex flavors?expand_more
This tool uses the JavaScript regex engine built into your browser. It supports standard regex syntax including character classes, quantifiers, groups, lookaheads, lookbehinds, and Unicode properties. Note that some features specific to other flavors (PCRE, .NET, etc.) may not be available.
Can I use this for email or URL validation?expand_more
Yes! Use the quick-insert buttons to load pre-built patterns for common validation tasks like emails, URLs, phone numbers, IP addresses, dates, HTML tags, and numbers. These patterns are ready to use and can be customized for your specific requirements.