Online Tool Store
Regex Tester
Test a regular expression against your own text, with matches highlighted live and a list of each match's position and captured groups. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Highlighted matches
Matches
How it works
- Enter a regex pattern and any flags.
- Paste or type test text.
- Matches are highlighted live, with a list of each match's position and captured groups.
FAQ
Which regex flavor does this use?
Your browser's native JavaScript regex engine — the same one behind String.match() and RegExp. Syntax generally matches other regex flavors, with a few JavaScript-specific details (like named groups and lookbehind support varying by browser).
What do the flags mean?
"g" finds all matches instead of stopping at the first; "i" makes matching case-insensitive; "m" makes ^ and $ match line boundaries; "s" lets . match newlines.
Why do I only see one match without the "g" flag?
Without the global flag, JavaScript's regex matching stops at the first match — add "g" to find every occurrence in the text.
Is my pattern or test text uploaded anywhere?
No — matching happens entirely in your browser as you type.
How we compare
| Feature | Online Tool Store | Testing in your code directly | Other online regex testers |
|---|---|---|---|
| No file upload — runs in your browser | ✓ | ✓ | ✗ |
| No re-running your app to see a match | ✓ | ✗ | ✓ |
Testing a regex inside your actual codebase means a rebuild-and-rerun loop for every tweak. Regex Tester updates matches instantly as you edit the pattern.