Regular Expression Tester
Test JavaScript regular expressions against sample text and inspect every match.
Test regular expressions
Use JavaScript regular-expression syntax and flags such as g, i, m, s and u.
Avoid running untrusted expressions against extremely large text because inefficient patterns can be slow.
How to use the Regular Expression Tester
- Provide the complete value or source material you want to inspect.
- Run the check and review each result or warning.
- Correct the original source and repeat the check before using it.
Practical example
Use a small known sample first so you can compare the output before processing a larger value.
What this tool cannot guarantee
The result reflects the supplied input and browser implementation; project-specific syntax and runtime behavior still require testing.
Continue this workflow with the JSON Formatter & Validator
Frequently asked questions
Is the Regular Expression Tester free to use?
Yes. It is available without an account or paid subscription.
Is my input uploaded or stored?
The core operation runs in your browser. Avoid pasting secrets into any web page unless the individual tool explicitly explains how the data is handled.
Should I review the result before using it?
Yes. Check the output for your project and test it in the intended environment before production use.