Regex Tester
Test regular expressions live with match highlighting, capture groups and replace.
3 matches
🔒 Your pattern and text never leave your browser.
What you can do
Enter a pattern and a test string to see every match highlighted in place, with a total match count. Toggle the g, i, m, s, u and y flags as checkboxes, and start instantly from the built-in email, number or date example patterns.
Groups and replace
Each match shows the matched text, its start index, and both numbered ($1, $2) and named (?<name>) capture groups. Turn on Replace mode to preview a .replace() result using $1, $<name> and $&; the g flag is required to replace every match instead of just the first.
Private by design
It runs on the browser's built-in RegExp engine, so it behaves exactly like your code, and your pattern and text never leave your browser — safe for logs or strings that contain personal data.
Frequently asked questions
What happens if my regex is invalid?
The SyntaxError message is shown in a dedicated area and the tool keeps working. As soon as you fix the pattern, the highlights and match list recompute automatically.
Can I see capture and named groups?
Yes. Every match lists the matched text, its start index, numbered groups ($1, $2…) and named groups (?<name>), with any group that did not participate marked separately.
Is my pattern or text uploaded?
No. Everything runs in your browser with the native RegExp engine, so your pattern and test string are never sent to a server.