01 / Fast steps
- Enter a regular expression pattern.
- Optionally set flags (e.g. g, i, m).
- Paste the string to test against.
Regex Tester
Enter a pattern and a test string to see every match, its position and any captured groups, updated instantly as you type.
Updates instantly as you type
02 / Best for
- Building and debugging a validation pattern.
- Checking how many times a pattern matches a body of text.
- Verifying captured groups before using them in code.
03 / Keep in mind
- Uses the JavaScript regex engine, behavior can differ slightly from other languages.
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faq
Questions, answered.
01Which regex flavor is used?
This tool uses the native JavaScript RegExp engine, so behavior matches what you would get in a browser or Node.js.
02Can I use flags like i or m?
Yes, enter any combination of valid flags (g, i, m, s, u, y) in the flags field.
03Is Regex Tester free to use?
Yes, Regex Tester is completely free, with no sign-up and no usage limits. It runs entirely in your browser, so your data never leaves your device.