Postman - The Collaboration Platform for API Development
rubular - A ruby based regular expression editor
Insomnia REST - The most intuitive cross-platform REST API Client ð´
RegExr - RegExr.com is an online tool to learn, build, and test Regular Expressions.
RESTClient - RESTClient can be used to test variety of HTTP communications and RESTful webservices.
RegEx Generator - RegEx Generator is a simple-to-use application that comes with the brilliance of intuitive regex and is also helping you out to test the regex.