Regex Tester Online — Test Regular Expressions Instantly

Last updated: 2026-03-14

I have been writing regex for 12 years and I still test every pattern before using it in production. Not because I do not know regex — because regex is one of those things where being 99% sure means you are wrong 1% of the time, and that 1% will bite you in production at 3 AM.

Why You Need a Regex Tester

Writing regex in your head and hoping it works is like writing SQL without running it. You might be right, but why risk it? A regex tester gives you:

Instant visual feedback. See matches highlighted in real-time as you type.
Group extraction. See what each capture group matches, not just the full match.
Edge case testing. Paste 20 test strings and see which ones match and which do not.
Explanation. Break down the pattern into human-readable steps.

Common Regex Patterns (Copy-Paste Ready)

Pattern	Matches	Example
`^[\w.-]+@[\w.-]+\.\w{2,}$`	Email addresses	[email protected]
`^https?://[\w.-]+(?:/[\w.-])/?$`	URLs	https://example.com/path
`^\+?[1-9]\d{6,14}$`	Phone numbers (international)	+14155551234
`^\d{4}-\d{2}-\d{2}$`	Dates (YYYY-MM-DD)	2026-03-22
`^#?([0-9a-fA-F]{3}\|[0-9a-fA-F]{6})$`	Hex color codes	#ff5733
`^(?=.[A-Z])(?=.[a-z])(?=.*\d).{8,}$`	Strong password	Abc12345

Regex Flavor Differences

The same pattern can behave differently in JavaScript, Python, and PCRE. Our tester lets you switch between flavors:

JavaScript: No lookbehind in older browsers. \d matches only ASCII digits.
Python: re module. Named groups use (?P<name>...) syntax.
PCRE: Most feature-rich. Supports recursive patterns, atomic groups, and possessive quantifiers.

Test your regex — real-time matching, group highlighting, explanations.

Open Regex Tester →

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According to MDN Web Docs, JavaScript regular expressions follow the ECMAScript specification with some browser-specific extensions.

As Python documentation notes, Python regex supports Unicode matching by default in Python 3.