Regex Tester
Free
Test regular expressions with match highlighting and flags.
Runs 100% in your browser — data stays private
3 found
Hello World 123
#1 "Hello"@ index 0
#2 "World"@ index 6
#3 "123"@ index 12
About Regex Tester
Test and debug regular expressions in real time. Enter your pattern, set flags, and see matches highlighted instantly with detailed match information including index positions.
Regular expressions are essential for validation, parsing, and text processing. This tool helps you iterate on patterns quickly without writing test scripts.
Key Features
- Real-time regex matching
- Match highlighting in test string
- Support for g, i, m, s flags
- Match count and index details
- Error messages for invalid patterns
How to Use
- 1Enter your regex pattern.
- 2Select flags (global, case insensitive, etc.).
- 3Type or paste a test string.
- 4Review highlighted matches and match details.
Common Use Cases
Validating email, phone, or URL patterns
Extracting data from log files
Testing regex before adding to code
Learning regular expression syntax
Frequently Asked Questions
What regex flavor does this use?+
JavaScript regular expressions (ECMAScript), the same engine used in browsers and Node.js.
What do the flags mean?+
g = global (all matches), i = case insensitive, m = multiline (^/$ match line boundaries), s = dotall (. matches newlines).
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