Regex Tester
Test regular expressions live: see every match highlighted, with match count, groups and flags — invalid patterns show a clear error — free, fast and private.
Type a pattern and test text to see matches.
Highlighted matches will appear here.
How to use Regex Tester
- Type your regular expression (without the surrounding slashes).
- Pick flags: g for all matches, i for case-insensitive, m for multiline.
- Paste the text to test against.
- Matches are highlighted below with their count and captured groups.
Note: this tool runs in your browser. Nothing is uploaded.
Frequently Asked Questions
What flags can I use?
g finds all matches, i ignores case, m makes ^ and $ match line starts and ends, s lets . match newlines, u enables Unicode mode.
Why does my pattern show an error?
The pattern is not a valid JavaScript regular expression. The error message names the problem — fix the pattern and try again.
How are matches highlighted?
Each match is wrapped in a highlight in the preview below, and the match list shows the matched text plus any captured groups.
Is my text uploaded anywhere?
No. Testing runs entirely in your browser.