Free Online Regex Tester with Live Highlighting
Test and debug regular expressions with live match highlighting using HubKit's regex tester. Write your pattern, add flags, and see matches highlighted in your test string in real time. View match details including captured groups, positions, and the total match count. Supports JavaScript regex syntax.
How to Use
Enter your regular expression pattern and optional flags (g, i, m, s, u). Paste or type your test string in the input area. Matches are highlighted instantly, and a match list shows each match with its index position.
Features
- Real-time match highlighting as you type
- Support for all JavaScript regex flags (g, i, m, s, u)
- Match list with position and group details
- Error messages for invalid regex patterns
Frequently Asked Questions
What regex flavor does this tester use?
This tester uses JavaScript's built-in RegExp engine, which supports ECMAScript regex syntax. It includes features like lookahead, lookbehind (in modern browsers), named groups, and Unicode property escapes.
What does the g flag do?
The g (global) flag finds all matches in the string instead of stopping after the first match. Without it, only the first occurrence is matched.
Can I test regex for other languages like Python or PHP?
JavaScript regex is similar to most languages, but there are differences in features and syntax. This tester is accurate for JavaScript, Java, and C# regex. Python and PHP have additional features like possessive quantifiers and recursive patterns not available here.