JSFiddle is an online IDE service and online community for testing and showcasing user-created and collaborational HTML, CSS and JavaScript code snippets, known as 'fiddles'.

Vivix is described as 'Free, open-source JavaScript execution visualiser that runs entirely in your browser. No install. No account' and is an website in the development category. There are four alternatives to Vivix, not only websites but also apps for a variety of platforms, including Self-Hosted, Google Chrome, Mac and Windows apps. The best Vivix alternative is jsFiddle, which is free. Other great sites and apps similar to Vivix are JS Bin, Python Tutor and DevTools.
JSFiddle is an online IDE service and online community for testing and showcasing user-created and collaborational HTML, CSS and JavaScript code snippets, known as 'fiddles'.

JS Bin is a collaborative open source JavaScript debugging tool. Enter Javascript in one pane and HTML in the other and see the result; share using a short URL. Choose popular JS libs from a menu, so you don't have to remember the URL.

Python Tutor helps people overcome a fundamental barrier to learning programming: understanding what happens as the computer executes each line of a program's source code.

A free, open-source Postman-style API tester you run locally. Record browser requests, auto-generate chained tests, and ship them straight to your CI—no sign-ups, no cloud, just code.

