A useful tool when working with Regular Expression

I was working with replacing strings using Regular Expression today and I found this amazing tools which saved me a lot of trouble. It allow custom text string to perform the regular expression on, and you can toggle between 3 different regular expression syntaxes: PHP, JavaScript and Python. There are also useful tips on the right hand side as well as a regex syntax look up table. Overall, a very handy free tool.

You can find it at regex101.com.