Terms of Service
About this tool
This free browser utility tests ECMAScript regular expressions against text locally and can preview a replacement. Use it only if you agree to these terms.
Your responsibility
You retain ownership of your text. Processing it here does not grant permission to publish it. Only test text you are entitled to use. Review and test a pattern in your own environment before relying on it; keep your original text.
Limits
Matches come from the JavaScript RegExp engine built into your browser. This is not a PCRE, Python, RE2, Java or .NET tester, and a pattern that works here is not a guarantee that the same pattern behaves identically in another language or library; syntax such as recursion or atomic groups is not supported. The search runs in a separate worker with a hard time limit, but that limit is a mitigation, not a guarantee against a slow pattern: catastrophic backtracking can still consume CPU until the limit is reached. The tool lists at most 1,000 matches, shortens very long match values, and reports indices as UTF-16 positions; per-group positions require the d flag. Imported files must be UTF-8 and are limited to 2 MiB; pasted text is limited to 1,000,000 characters. Testing a pattern does not validate your data or prove a pattern is safe.
Privacy
Your pattern and text are processed locally as described in the Privacy Policy. Your original text is not overwritten.
Availability
The service is provided "as is" and "as available," without a guarantee of compatibility or uninterrupted operation. Nothing here limits rights that cannot lawfully be excluded.
Components
This tool uses only the JavaScript regular expression engine built into your browser and ships no third-party libraries, fonts or remote scripts.
Changes
Features and these terms may change; updated terms apply to later use.