Regex Tester
FreeTest and debug regular expressions with live match preview
About Regex Tester
Regular expressions are powerful and notoriously easy to get subtly wrong, and squinting at a pattern hoping it matches the right text wastes more time than it should. The Regex Tester from ToolHub by Codaiman lets you write a pattern, paste sample text, and see exactly what matches in real time as you type.
Enter your expression and test string, and the tool highlights every match and capture group live, so you can refine the pattern until it does precisely what you intend. It is the fastest way to build and debug a regex for validation, parsing, or search-and-replace before you commit it to code. Everything runs in your browser with no signup, giving instant feedback while your patterns and sample data stay entirely on your machine, free to use as often as you like.
Common uses
- Building and testing a validation pattern for emails, phone numbers, or postal codes
- Debugging why a regex matches too much or too little against real sample data
- Working out capture groups before using them in a search-and-replace operation
- Learning or teaching regex syntax with immediate visual feedback
- Verifying a pattern from someone else's code does what you expect before reusing it
How to use
- 1
Configure options
Set your preferences using the options panel below.
- 2
Click Generate
Click the process button to generate your result instantly.
- 3
Copy or download
Copy the result to clipboard or download it directly to your device.
Why ToolHub?
- Instant error detection
- Detailed error messages
- Standards compliant
FAQ
Does it show capture groups?
Yes. Matches are highlighted live and capture groups are surfaced so you can confirm the structure your pattern extracts.
Which regex flavor does it use?
It uses JavaScript-style regular expression syntax, which closely mirrors patterns used in many other languages for common cases.
Can I use flags like global and case-insensitive?
Yes, common flags such as global, case-insensitive, and multiline are supported to control how matching behaves.
Is my test data private?
Yes. Matching runs in your browser, so your patterns and sample text are never sent anywhere.
Can I use Regex Tester on mobile?
Yes — ToolHub is fully responsive and works on iPhone, Android, tablets and all modern browsers. No app install needed.