Which flavour of regex is used?

The tool uses PCRE, the engine behind PHP, which is close to what you will find in Perl, Python, and JavaScript for common patterns.

Why did my pattern fail?

The message explains the compile error, such as an unclosed group or an invalid escape. Check the delimiters and special characters.

Up to 50 matches are listed so the result stays readable. Refine the pattern if you need something more specific.

English

Developer

Test a regular expression against sample text.

Free · no sign-up Instant results Nothing stored

Ready when you are

Free to use · No signup required

Input

Result

Output appears hereFill in the fields, run the tool, and the result shows up right here with a one-click copy button.

About this tool

Try a regular expression against sample text and see each match. Testing patterns before shipping them avoids surprises in production code.

Learn more

Learn how to format JSON, understand parser errors, fix common syntax problems, and keep structured data readable during development.