Regex tester

Runs in your browser · No data sent

Test regular expressions live with match highlighting, capture groups and flag toggles.

How to use

Type a regular expression and some test text, and matches are highlighted live as you type. Toggle flags like global, case-insensitive and multiline, and see captured groups so you can confirm your pattern does exactly what you intend before using it in code.

It's the fastest way to build and debug a regex without re-running your program — tweak the pattern and instantly see what matches and what doesn't. Everything runs in your browser using the native JavaScript regex engine.

Because nothing is sent to a server, you can safely test patterns against real data like logs or sample records.

Examples

Validate an email

Test an email pattern against good and bad samples to catch edge cases.

Extract with groups

Use capture groups to pull dates or IDs out of a line of text.

Find and check

Confirm a search-and-replace pattern matches only what you expect before running it in code.

Frequently asked questions

Which regex flavour does it use?

JavaScript (ECMAScript) regular expressions, since it runs the browser's built-in engine. Most patterns are portable, but some syntax differs from PCRE or Python.

What do the flags do?

g matches all occurrences, i ignores case, m makes ^ and $ match line starts/ends, and s lets the dot match newlines.

Does it show capture groups?

Yes. Matched groups are listed so you can verify what each part of your pattern captured.

Is my test data uploaded?

No. Matching happens in your browser, so your pattern and text stay private.