Regex Tester
Test and debug regular expressions with real-time match highlighting and detailed results
Regular Expression Pattern
Flags:
Samples:
Test String
Highlighted Matches
Privacy First: All regex testing happens locally in your browser. No data leaves your device.
What are Regular Expressions (Regex)?
Regular Expressions, or Regex, are powerful strings of characters used to define search patterns. They are widely used in programming for string validation, search-and-replace operations, and complex data extraction.
Our Regex Tester allows you to write, test, and debug these patterns with real-time feedback and detailed match groups, all within a privacy-first environment.
Common Regex Tokens & Syntax
\d: Matches any digit (0-9).\w: Matches any word character (Alphanumeric + underscore)..: Matches any character except newlines.+: Matches 1 or more of the preceding token.
^: Matches the start of a string.$: Matches the end of a string.[abc]: Matches any character in the set (a, b, or c).(abc): Creates a capture group.
Understanding Regex Flags
Flags modify how the engine interprets your pattern:
- g (Global): Don't return after the first match; find all matches in the string.
- i (Ignore Case): Make the pattern case-insensitive.
- m (Multiline): Treat start (
^) and end ($) characters as line boundaries rather than string boundaries.
Why Test Regex Locally?
When you're debugging regex for sensitive logs or user data, you shouldn't send that data to an external server. Our Regex Tester uses the native JavaScript RegExp engine in your browser, ensuring that your test strings and patterns stay on your machine.
🔒 Privacy Commitment
Like all tools in the Dev Tool Kit, this Regex Tester operates 100% client-side. Your data is processed locally in your browser and is never sent to our servers. Privacy is not just a feature; it's our core architecture.