Regular Expression Tester and Replace Tool
Check JavaScript/ECMAScript regular expression match locations, capture groups, and replacement results in real time.
The regular expressions, text, and files you enter are processed only in your browser and are not sent to or stored on servers. Some syntax and behavior differ from Java, Python, .NET, PCRE, and others.
regular expression
test string
Match point
Replace test
Simple explanation of regular expressions
A simple explanation of the main symbols. It does not guarantee the validity of the entire regular expression.
Match list
| No. | match | position | row:column | capture group |
|---|
Condition:
Match: 0
Processing time: -
About this tool
Before adding a regular expression to your code, check its match positions, captured values, and replacement output against sample text.
Features
- JavaScript and ECMAScript regular expressions with the g, i, m, s, u, v, and y flags
- Highlighted matches, line and column positions, numbered and named captures, and replacement results
How to use
- Enter a regular expression or select a preset for a common use case.
- Enter test text or load a local text file from your device.
- Review the matched text, capture groups, and replacement result.
Limitations
- Some syntax and behavior differ from regular expressions in Java, Python, .NET, PCRE, and other engines.
- The performance warning is a heuristic and does not detect every ReDoS risk.
Privacy: Selected files and conversion or analysis results are processed in your browser and are neither sent to nor stored on the Develop Tools server.