Regex Tester
Test regular expressions with match highlighting, capture groups, and replace preview. Free, private, and 100% client-side.
Local only
Recent history
No history yet
How to use
- Enter the regular expression pattern.
- Paste the test text into the input box.
- Toggle flags and read matches with capture groups.
Frequently asked questions
- What happens with catastrophic backtracking?
- Matching runs in a Web Worker with a timeout. If it exceeds the limit, the tool reports a timeout instead of freezing the page.
- Which flags are supported?
- Global (g), ignore case (i), multiline (m), and dotAll (s) can be toggled independently.