What regex flavor does this use?

This tester uses JavaScript (ECMAScript) regex syntax, which is supported in all modern browsers. It covers the vast majority of regex patterns used in web development, Node.js, and most programming languages.

What does the global flag (g) do?

Without the global flag, the regex stops after the first match. With the g flag enabled, all matches in the input string are found and highlighted. Most use cases require the global flag.

How do capture groups work?

Parentheses create capture groups: (\d+) captures one or more digits. Each group is numbered from left to right starting at 1. Named groups use (? ...) syntax. The results panel shows each match and its captured sub-groups separately.

Can I test multiline strings?

Yes. Use the m (multiline) flag to make ^ and $ match the start and end of each line rather than the whole string. Paste multiline text directly into the test string field.

🔍

Regex Tester

Test and debug regex in real time. Highlights all matches, shows capture groups, supports all flags. Free browser-based regex tester.

About this tool

Test and debug regular expressions instantly with real-time match highlighting. See all matches, capture groups, and named groups. Supports all JavaScript regex flags: global, case-insensitive, multiline, dotAll, unicode, and sticky.

Regular Expression

//gi

Test String

Match Preview2 matches

Contact us at hello@yourtoolskit.com or support@example.org for help.

Match Details

#1hello@yourtoolskit.comindex: 14

#2support@example.orgindex: 40

How we calculate this

All calculations run entirely in your browser — no data is sent to any server. Here is exactly how this tool works:

Enter your regular expression in the pattern field
Select any flags (g, i, m, s, u, y)
Paste your test string — matches highlight immediately
Inspect each match and its capture groups below

Frequently Asked Questions

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📱Works on mobile & desktop