Regex Tester

Test regular expressions live with match highlighting and group capture support.

The Regex Tester is a completely free online tool that requires no sign-up or account. Test regular expressions live with match highlighting and group capture support. Instant results in your browser — no downloads, no limits.

⚙️ Pattern
/ /
📊 Results
0 matches found
Enter a pattern and test string above...

What is Regex Tester?

The Regex Tester is a free online tool that allows developers to write, test, and debug regular expressions in real time against any sample text. Regular expressions are powerful patterns used to search, validate, and manipulate strings in virtually every programming language. This tool highlights matches instantly as you type, supports common flags like global, case-insensitive, and multiline, and helps you build accurate patterns without trial and error in your codebase.

How to Use the Regex Tester

  1. Enter your regular expression pattern in the pattern input field.
  2. Set any desired flags such as g (global), i (case-insensitive), or m (multiline).
  3. Paste your test string into the text area below.
  4. All matches will be highlighted in real time as you type.
  5. Review the match details panel to inspect captured groups.

Frequently Asked Questions

What is a regular expression?
A regular expression (regex) is a sequence of characters that defines a search pattern, commonly used for string validation, parsing, and find-and-replace operations.
Which regex flavor does this tester use?
This tester uses JavaScript regex syntax, which is compatible with most modern programming languages and covers the majority of common use cases.
What does the global flag do?
The global flag (g) tells the regex engine to find all matches in the input string rather than stopping after the first match.
Can I use this to validate email addresses or phone numbers?
Yes, you can enter a validation pattern for emails, phone numbers, or any format and test it against sample inputs to confirm it matches correctly.

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