Regex Tester

Test regular expressions quickly — preview matches, capture groups, and replacements.

Regex

Do not include surrounding slashes /.../ — choose flags below.
Use JS replacement syntax: $&, $1, $2, $`, $'
Matches

Preview & Result

Highlighted Preview
Replacement Result
 
Notes: This tester uses JavaScript RegExp semantics (Chrome/Edge/Firefox). For server-side .NET regex testing, the behavior may differ.
Regex Tester – Test, Debug, and Replace Online
Regular Expressions (Regex) are powerful for matching, searching, and replacing patterns in text. But writing them can be tricky. That’s where our free Regex Tester online comes in. With this tool, you can easily test your regex patterns, preview matches, check capture groups, and even perform replacements instantly.
What is a Regex Tester?
A Regex Tester (regular expression tester) is an online utility that helps you verify your regex syntax and see how it works on sample text. Instead of guessing, you get real-time feedback with highlighted matches and replacement results.
Features of Our Regex Tester Tool
  • Enter your regex pattern and select flags (g, i, m, s, etc.).
  • Paste your test string and see all matches highlighted.
  • View detailed match info with capture groups and positions.
  • Try replacements using $1, $2, and other regex replacement variables.
  • Copy or download your results instantly.
Why Use an Online Regex Tester?
  • Saves time while building complex regex patterns.
  • Debug errors quickly with instant feedback.
  • No need to write extra code — test everything in the browser.
  • Works for developers, data analysts, testers, and anyone working with text processing.
Examples You Can Try
  • (\d{3})-(\d{3})-(\d{4}) → Matches phone numbers like 123-456-7890
  • [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} → Matches emails
  • https?:\/\/[^\s]+ → Matches URLs
  • \b(\d{2})[-\/](\d{2})[-\/](\d{4})\b → Matches dates like 12/09/2025
How to Use the Regex Tester Tool?
  1. Enter your regex pattern (without / slashes).
  2. Select regex flags like global, ignore case, or multiline.
  3. Paste the text you want to test against.
  4. See matches highlighted in real time.
  5. Use the replace option to preview substitution results.
Conclusion
Our online Regex Tester is the fastest way to debug and validate your regular expressions. Whether you’re a beginner or a pro developer, this free tool will help you master regex with ease. Try it now and simplify your text-processing tasks.
 🚀 Try Free Regex Tester