I have something to admit... I'm a RunKit addict. It is simply fantastic!
There are many use cases, I'd like to share. But first, what is RunKit?

What is RunKit?

It is a node.jsREPL. Of course node.js comes with it's own REPL:

node> 1 + 2> // 3

So why bother with RunKit? NPM. RunKit comes with every NPM module pre-installed. That is crazy powerful! Let's proceed to some use cases.

Use Cases

1) You want to audition an NPM module

If you want to try a module without installing it first, RunKit is your friend! Let's see a quick example. Say for instance you want to trydate-fns.

How is that for a quick feedback loop? Keep in mind you are not limited to a single module. You can require as many as you'd like.

2) Embedded Code Samples

So what, we already havegist right? Well, RunKit embeds are executable and modifiable. That's right, you can try the code inside an article or documentation page!

Embed RunKit

3) Saved Snippets

RunKit also saves your notebooks to your account. I find this extremely useful. I find myself going back to my saved notebooks weekly.

That's about it for now. Please share anything I missed in the comments :)