RegExr.com is an online tool to learn, build, and test Regular Expressions. It was created by Grant Skinner and the nice people at gskinner.com.

• Results update in real-time as you type.
• Supports JavaScript & PHP/PCRE RegEx.
• Roll over a match or expression for details.
• Save & share expressions with others.
• Use Tools to explore your results.
• Browse the Reference for help & examples.
• Undo & Redo with cmd-Z / Y in editors.
• Search for & rate Community patterns.

Please report issues & feature requests on GitHub.

This version of RegExr is not open source (yet).

I'm a firm proponent of open source, but it provided negligible benefits for the project, and formed the foundation for a number of competitive sites, many of which did not open source their own work. This wasn't a requirement by any means, but it created a value imbalance. RegExr will probably be open sourced again in the future, but I am considering releasing it under GPL to encourage people building on it to share alike.

Feedback on this decision is very much welcomed. If you're interested in using the source for something in the interim, feel free to get in touch.