Insomnia REST - The most intuitive cross-platform REST API Client ð´
CodePen - A front end web development playground.
Postman - The Collaboration Platform for API Development
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.
Hurl.it - Hurl makes HTTP requests.
replit - Code, create, andlearn together. Use our free, collaborative, in-browser IDE to code in 50+ languages — without spending a second on setup.