Features

Test and debug regular expressions in real time with live match highlighting. Supports JavaScript regex syntax, replacement patterns, and match groups. No signup, no upload — works entirely in your browser.

When You Need This

Common pain points this tool solves

1. Debug complex regex patterns while writing code
2. Extract emails, URLs, phone numbers from text blocks
3. Validate user input formats (emails, phone numbers, postcodes)
4. Find and replace text using capture groups

How to Use

Step-by-step instructions

1. Paste your sample test text into the left input box, then type your regex pattern into the pattern field
2. Toggle the global, case-insensitive, and multiline flags as needed for your target environment
3. Review the highlighted matches on the right and inspect the captured groups list to confirm every field lines up
4. Copy the final regex, import it from the template gallery, or save it for reuse across projects

Why Choose Korelyy

What makes us better

1. Real-time match highlighting as you type
2. Full JavaScript regex syntax support with flags (g, i, m, s, u)
3. Match groups and named groups displayed clearly
4. Replacement pattern tester with live preview
5. Share regex patterns via URL encoding

Monetize With This Tool

Turn this tool into a side income stream

1. Use this tool to speed up your freelance work and take on more paying clients
2. Create polished content faster for your blog, YouTube channel, or social media and grow your audience
3. Offer this tool's capabilities as a service on Fiverr, Upwork, or to your local business clients

Frequently Asked Questions

1. Is Regex Tester — Test Regular Expressions Online free to use?

   Yes. Regex Tester — Test Regular Expressions Online is 100% free for core features — no signup, no watermarks, no hidden paywalls on the tools you need day to day.

2. Do I need to sign up to use Regex Tester — Test Regular Expressions Online?

   No. Open and use instantly in your browser. Nothing to install, no account required. Your preferences stay on your device.

3. Is my data safe with Regex Tester — Test Regular Expressions Online?

   Yes. Regex Tester — Test Regular Expressions Online runs locally in your browser whenever technically possible — sensitive inputs are processed on your device, not on our servers. No tracking cookies.

4. Which devices does Regex Tester — Test Regular Expressions Online work on?

   Phones, tablets and desktops with any modern browser (Chrome, Safari, Edge, Firefox). Touch-friendly and responsive from 320px to 4K.

5. How do I test a regex pattern against multiple strings?

   Enter your regex pattern in the top field and add multiple test strings separated by new lines in the test area. The tool highlights matches in real-time and shows capture groups. You can also toggle flags like global (/g), case-insensitive (/i), and multiline (/m).

6. What regex flavors does this tester support?

   This tester uses JavaScript/ECMAScript regex syntax, which covers most common patterns used in web development. It supports lookahead/lookbehind assertions, named capture groups, and Unicode property escapes.

7. Can I save and share my regex patterns?

   Yes, you can save patterns to your browser local storage and come back to them later. You can also copy the regex as a shareable URL to send to colleagues.