Question 1

How do I test a regular expression online?

Accepted Answer

Go to regex.toolzydev.com, type your regex pattern in the pattern bar at the top, and enter your test string in the Test String panel. Matches are highlighted in real time as you type.

Question 2

What are capture groups in regex?

Accepted Answer

Capture groups are portions of a regex pattern enclosed in parentheses, e.g. (\d+). They capture the matched substring so you can reference it later. The Results panel shows each capture group value for every match.

Question 3

How do I use the replace feature?

Accepted Answer

Enter your regex pattern in the pattern bar, type a replacement string in the Replace bar at the bottom, and click Replace All. You can use $1, $2, etc. to reference capture groups in the replacement.

Question 4

What regex flags are supported?

Accepted Answer

Regex Tester supports four flags: g (global — find all matches), i (case-insensitive), m (multiline — ^ and $ match line boundaries), and s (dotAll — dot matches newlines). Toggle them individually with the flag buttons.

Question 5

Is this regex tester free?

Accepted Answer

Yes, Regex Tester at regex.toolzydev.com is completely free. No login or installation required. All regex processing happens locally in your browser — your data is never sent to a server.