Function as a Service seems to be the new black. But what is it? This brief post will explain it.

First, there was a Function

Here is the function, saved to the faas.js file:

module.exports = function (ctx, cb) {
    cb(null, 'Hello from a Function');

Second, we make it a Service

Now, we convert the function to a service with wt-cli:

npm install -g wt-cli
wt init
wt create faas.js

Voila, Function as a Service

What comes back is a URL, which is the Function as a Service. It may look like this:

Go ahead and call it. It is a service.

Wait, what just happened?

We have used the CLI of Auth0 Webtasks to turn a Node.js function into an HTTP endpoint that can be called from a mobile or HTML5 app, or just with curl. Auth0 Webtasks is all about making developer's life simple - all you need is a function. Webtasks turn it into service. Learn more at

Function as a Service vs Serverless

How is Function as a Service (FaaS) different from serverless? It is not. At the core it represents the same trend explained in the What is serverless? and on Martin Fowler's blog Serverless Architectures.

The key difference is emotional. The term server-less is both inacurate (there are still servers involved), as well as socially controversial, since it suggests looming structural unemployment of swaths of IT personel who make their living by running those servers today. The Function as a Service (FaaS) term is clearly less radioactive. Read more about the merit of the trend at What is serverless.

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Tomasz Janczuk



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