Regex Tester
Test regular expressions against your own text with live match highlighting and capture group details.
Runs entirely in your browser — your files are never uploaded to a server.
How It Works
1. Choose Your File
Drag & drop or select the file you want to work with.
2. Processed in Your Browser
Everything happens locally on your device — your file is never uploaded anywhere.
3. Download Your Result
Get your finished file instantly, ready to save or share.
Frequently Asked Questions
What regex flags are supported?
g (global), i (ignore case), m (multiline), and s (dotAll) — toggle any combination to match your use case.
Can I see capture groups from my matches?
Yes, each match shows its capture groups individually below the match itself.
What happens if my regex has a syntax error?
You'll see a clear error message describing what's wrong, rather than a silent failure.
Is this using JavaScript's regex engine?
Yes — it uses your browser's native RegExp engine, so behavior matches exactly what you'd get writing regex in JavaScript.