Serverless Doesn't Exist, It's Just Someone Else's Computer

As some of you may know, I was sick this weekend, but Jingna Zhang must have gotten even sicker when she saw her Vercel bill after her app went viral.

The app in question is Cara, an app for artists that allows them to upload images and build a portfolio. The interesting thing about this app is that it's exclusive to the niche; for example, it has a job offers section where all posts are for artists.

Everything was going well until last week when Cara went viral in the Apple App Store and went from 40,000 users to 650,000 in just a few days.

So far so good, honestly, it's anyone's dream to have an app go viral and be able to live off it.

The problem? It's simple: serverless, contrary to what its name suggests, doesn't mean there are no servers, but rather it's someone else's server that you rent and which can scale endlessly.

In this case, that caused a bill of 96,280 USD in just a few days. This isn't the only case we've seen recently; both Vercel and similar services like Firebase or Netlify show similar stories almost every month.

1- The Real Costs of Serverless

At first glance, a serverless solution can be very attractive. Generally, it's relatively quick to develop and manage these types of applications, as the service provider is responsible for security, updates, and most of the configuration, allowing you as a developer to focus solely on your code and connecting your application to other apps, databases, etc.

Additionally, the payment model for serverless applications is pay-as-you-go. This means if your app isn't used, you don't pay anything. But it also means that if you get a lot of traffic, the costs will soar, and that's exactly what happened to Cara. They went from 40k users to 650k and expenses skyrocketed.

Serverless applications have become very popular lately in the enterprise world. Even though they're expensive to maintain under heavy use, if your app is B2B (business to business), the usage isn't usually excessive, making it quite affordable, plus you save on all the maintenance hassle.

BUT if it's your own app, maybe it's not the best idea.

1.1 - Added Costs of Vercel

I'm talking about Vercel in this post because it's the relevant platform, but this applies to any similar platform like Netlify, Firebase, etc.

These platforms are an additional layer on top of a cloud provider like AWS or Azure. They make it easy; configuring AWS is complicated if you don't have experience, and Vercel lets you focus only on what's important: your application logic.

The point is, these apps need to make money somehow, so they add extra charges on top of the cloud provider's price.

2 - Alternatives to Serverless

While it's true that Vercel lets you set a spending limit, after which your app will stop working, it's not an ideal solution.

In my opinion, the ideal solution is to ditch serverless and leave it to those companies that truly need to scale endlessly during peak times. The best thing we can do is to get a traditional server (VPS).

A web server costs very little, especially in its lower ranges, where the worst-case scenario if your app goes viral is that it stops working. In my opinion, that's a better option than a nearly 100k USD bill.

I’ve always been a big fan of VPS because of their predictable and fixed cost. In fact, my blog is on one, I pay 10 euros a month and have several apps plus the blog and the database, and even though I get less than 6,000 daily visits, this server (based on the stats) should be able to handle 15 or even 20 times that traffic.

NOTE: Image from ovh.

And that's for a small server; 10 euros a month is really nothing. Now imagine if you upgraded to a 300 or even 400 euro server.

We're talking 48 vCPUs and 190 GB RAM, the amount of hardware you could buy or rent with the 96k euro Vercel bill is almost endless.

Those 350 euros should be enough for the 65,000 users the app had before going viral, and more for plenty beyond that. But in the worst case, you just need to get one, two, or ten more and put a load balancer in front, it's always going to be cheaper than the crazy bill this person got.

Of course, with a VPS you have to configure everything yourself, from the reverse proxy to the app itself, but that's a cost I personally am willing to pay.

Link to Digital Ocean.

Note: Here's a list of posts on how to set up an app on a Linux server with SQL, reverse proxy, etc..