Regex Tester & Debugger
Highlight, capture, replace, and export code. Runs in a safe worker.
Regex playground workspace
Loading regex tools…
About Regex Playground
Build and debug JavaScript-compatible regular expressions without sending test data away. Inspect match ranges, numbered and named capture groups, replacement output, and ready-to-adapt code.
How to use
- Enter a pattern, enable the required flags, and paste test text.
- Inspect highlighted matches and every numbered or named capture group.
- Preview a replacement or copy a JavaScript, Python, or Go starting point.
FAQ
Can a regular expression freeze the page?
Pattern execution runs in a separate browser worker with a short timeout. Expressions with catastrophic backtracking are stopped instead of blocking the interface.
Which regex syntax does this tester use?
Matching uses the JavaScript RegExp engine. The Python and Go tabs are starter snippets; syntax or behavior can differ for engine-specific features.
Is my test text uploaded?
No. The pattern, test text, match list, captures, and replacement stay in this browser.