Is my text sent anywhere?

No. The pattern is executed by your browser's regex engine locally. Nothing is transmitted or stored.

Which regex dialect is this?

JavaScript's. Most everyday syntax is shared with PCRE, but PCRE-specific features such as atomic groups, recursion and possessive quantifiers do not exist here, and named groups use (? …).

Why does my pattern only find one match?

The global flag is off. Without it, matching stops at the first result.

Regex Tester

Runs in your browser

Test a regular expression against sample text with live matches, capture groups and a replace preview. Runs in your browser.

Pattern

//g

Test string

2 matches

"hello@snaptools.in" at 8 · groups: "hello""snaptools.in"
"sales@knklabs.com" at 30 · groups: "sales""knklabs.com"

Replace with (optional — $1 for group 1)

About this tool

Regular expressions fail in ways that are hard to see by reading them: a greedy quantifier swallows more than intended, an unescaped dot matches any character, or a missing global flag returns only the first result. Testing against real sample text turns that guesswork into feedback. This tester uses the browser's own regex engine — the same one your JavaScript will use — so what you see here is what your code will do.

How to use

Type your pattern without the surrounding slashes.
Toggle the flags you need — global is on by default so you see every match.
Paste representative sample text, including the cases you expect to fail.
Optionally enter a replacement to preview the result; $1 and $2 refer to capture groups.

When to use this tool

Working out why a validation pattern rejects valid input.
Extracting fields from log lines or scraped text.
Building a find-and-replace before running it across a codebase.
Learning what a regex someone else wrote actually does.

Tips

Test the failure cases, not just the ones you expect to match — that is where regexes usually go wrong.
Use non-greedy quantifiers like .*? when matching between delimiters.
Anchors ^ and $ match string start and end unless the multiline flag is set, when they match each line.

Limitations

Uses the JavaScript regex engine. PCRE features such as lookbehind variants, atomic groups and recursion behave differently or are unsupported.

FAQ

Is my text sent anywhere?: No. The pattern is executed by your browser's regex engine locally. Nothing is transmitted or stored.
Which regex dialect is this?: JavaScript's. Most everyday syntax is shared with PCRE, but PCRE-specific features such as atomic groups, recursion and possessive quantifiers do not exist here, and named groups use (?<name>…).
Why does my pattern only find one match?: The global flag is off. Without it, matching stops at the first result.