Regex Tester
Test regular expressions with live matching, highlighting, and common pattern presets.
Contact us at hello@example.com or support@utylo.com for help.
#1 "hello@example.com" at index 14
#2 "support@utylo.com" at index 35
Key Features
- Tests regular expressions against sample text with live match highlighting.
- Displays all matches, captured groups, and their index positions in the input string.
- Supports JavaScript regex flags: global, case-insensitive, multiline, dotAll, and unicode.
- Shows a real-time explanation of what each part of the regex pattern matches.
- Runs entirely in the browser — your patterns and test strings stay on your device.
- Colour-codes different capture groups to make complex patterns easy to follow.
Frequently Asked Questions
What regex flavour does this tester use?
The tester uses JavaScript's built-in RegExp engine. This is the same engine used in Node.js and all modern browsers, making it ideal for frontend and backend JavaScript development.
Why is my regex matching too much or too little?
Quantifiers like * and + are greedy by default, matching as much as possible. Append a ? to make them lazy (e.g. *?), which matches as little as possible. The live highlighting makes it easy to spot the difference.
Is my regex or test data sent to a server?
No. The matching runs locally in your browser using the native JavaScript RegExp API. Nothing is transmitted to any server.