What regex flavor does this tool use?

This tool uses JavaScript's built-in RegExp engine, which supports ECMAScript regular expressions including features like lookaheads, lookbehinds, and named groups.

What are the available flags?

You can toggle g (global), i (case-insensitive), m (multiline), and s (dotAll) flags using the checkboxes.

How are matches displayed?

Matches are highlighted inline in the test string. Capture groups for each match are shown in cards below the highlighted text.

Is my data sent to a server?

No. All regex testing happens locally in your browser. Nothing is transmitted anywhere.

Regex Tester

Test regular expressions with real-time match highlighting and capture groups.

Pattern

g(global)i(case-insensitive)m(multiline)s(dotAll)

Test String

How to Use Regex Tester

Step 1

Enter your regular expression pattern.

Step 2

Toggle the flags you need (g, i, m, s).

Step 3

Type or paste your test string.

Step 4

View highlighted matches and capture groups in real time.

Features

Real-time regex matching as you type.

Interactive flag toggles for g, i, m, and s.

Inline match highlighting in the test string.

Capture group details shown for each match.

Completely client-side — no data leaves your browser.

FAQ

: This tool uses JavaScript's built-in RegExp engine, which supports ECMAScript regular expressions including features like lookaheads, lookbehinds, and named groups.
: You can toggle g (global), i (case-insensitive), m (multiline), and s (dotAll) flags using the checkboxes.
: Matches are highlighted inline in the test string. Capture groups for each match are shown in cards below the highlighted text.
: No. All regex testing happens locally in your browser. Nothing is transmitted anywhere.