Free browser utility
Regular Expression Tester
Debug validation patterns, search expressions and text transformations.
✓ Local processing✓ No registration✓ No file upload
Loading tool…
Before
Pattern: (\w+)@(\w+\.\w+) Text: mail@example.com
→
After
Match 1: mail@example.com Group 1: mail Group 2: example.com
How to use Regular Expression Tester
- Paste text or select local files in the tool area.
- Choose any options that match the source data.
- Run the conversion or repair and review the preview.
- Copy the result or download the generated file.
Privacy and local processing
This project performs processing, document generation or calculations in your browser. The page does not include an upload endpoint, analytics script or remote processing API call. Avoid pasting sensitive data into websites you do not control.
What this tool includes
- Runs locally in the browser.
- Includes copy and download actions.
- Designed for focused developer troubleshooting.
Common uses
- Debug validation patterns, search expressions and text transformations.
- Useful for testing, documentation and small data-cleaning tasks.
Practical tips
- Test generated output before using it in production.
- Keep a backup before replacing configuration or source files.
Frequently asked questions
Is my data uploaded?
No. This tool processes the entered data locally in your browser.
Should I use the result directly in production?
Review and test generated or transformed output in a safe environment before deploying it.