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Regex Tester

Test regular expressions in real-time with instant match highlighting, capture group visualization, and replace mode. Built on the native JavaScript RegExp engine.

Pattern
//g
Test String4 matches found
1
2
Contact us at hello@example.com or support@toolvs.co for help.
Also try admin@test.org and info@company.net
Match Results
1"hello@example.com"
idx 14..30
Group 1:"hello"
Group 2:"example"
Group 3:"com"
2"support@toolvs.co"
idx 35..51
Group 1:"support"
Group 2:"toolvs"
Group 3:"co"
3"admin@test.org"
idx 72..85
Group 1:"admin"
Group 2:"test"
Group 3:"org"
4"info@company.net"
idx 91..106
Group 1:"info"
Group 2:"company"
Group 3:"net"
Common PatternsClick to insert

Frequently Asked Questions

What is a regular expression?

A regular expression (regex) is a sequence of characters that defines a search pattern. It is used for string matching, validation, and text manipulation across virtually all programming languages.

How do regex capture groups work?

Capture groups are created by wrapping part of a regex pattern in parentheses. When a match is found, each group captures the substring it matched, which can be referenced by index. Named groups use (?<name>...) syntax.

What do regex flags mean?

Flags modify regex behavior: g (global) finds all matches, i (case-insensitive) ignores case, m (multiline) makes ^ and $ match line boundaries, s (dotAll) makes . match newlines, and u (unicode) enables full Unicode support.

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