We have a lot of experience in JavaScript, writing our services in NodeJS allows developers to transition to the back end without any friction, without having to learn a new language. There is also the option to write services in TypeScript, which adds an expressive type layer. The semi-shared ecosystem between front and back end is nice as well, though specifically NodeJS libraries sometimes suffer in quality, compared to other major languages.

As for why we didn't pick the other languages, most of it comes down to "personal preference" and historically grown code bases, but let's do some post-hoc deduction:

Go is a practical choice, reasonably easy to learn, but until we find performance issues with our NodeJS stack, there is simply no reason to switch. The benefits of using NodeJS so far outweigh those of picking Go. This might change in the future.

PHP is a language we're still using in big parts of our system, and are still sometimes writing new code in. Modern PHP has fixed some of its issues, and probably has the fastest development cycle time, but it suffers around modelling complex asynchronous tasks, and (on a personal note) lack of support for writing in a functional style.

We don't use Python, Elixir or Ruby, mostly because of personal preference and for historic reasons.

Rust, though I personally love and use it in my projects, would require us to specifically hire for that, as the learning curve is quite steep. Its web ecosystem is OK by now (see https://www.arewewebyet.org/), but in my opinion, it is still no where near that of the other web languages. In other words, we are not willing to pay the price for playing this innovation card.

Haskell, as with Rust, I personally adore, but is simply too esoteric for us. There are problem domains where it shines, ours is not one of them.

With Python + Django it was so much faster to create a typical website like this. Using Go would take to long to launch the initial version. For example, Python could handle complex data type with less line of code. Django also has many built-in libraries and a huge ecosystem of libraries that can be easily used to build a feature.

Starting a new company in 2020, with a whole new stack, is a really interesting opportunity for me to look back over the last 20 years of my career with web software and make the right decision for my company.

And, I went with the most radical decision– which is to ignore "sexy" / "hype" technologies almost entirely, and go back to a stack that I first used over 15 years ago.

For my purposes, we are building a video streaming platform, where I wanted rapid customer-facing feature development, high testability, simple scaling, and ease of hiring great, experienced talent. To be clear, our web platform is NOT responsible for handling the actual bits and bytes of the video itself, that's an entirely different stack. It simply needs to manage the business rules and the customers experience of the video content.

I reviewed a lot of different technologies, but none of them seemed to fit the bill as well as Rails did! The hype train had long left the station with Rails, and the community is a little more sparse than it was previously. And, to be honest, Ruby was the language that was easiest for developers, but I find that most languages out there have adopted many of it's innovations for ease of use – or at least corrected their own.

Even with all of that, Rails still seems like the best framework for developing web applications that are no more complex than they need to be. And that's key to me, because it's very easy to go use React and Redux and GraphQL and a whole host of AWS Lamba's to power my blog... but you simply don't actually NEED that.

There are two choices I made in our stack that were new for me personally, and very different than what I would have chosen even 5 years ago.

1) Postgres - I decided to switch from MySql to Postgres for this project. I wanted to use UUID's instead of numeric primary keys, and knew I'd have a couple places where better JSON/object support would be key. Mysql remains far more popular, but almost every developer I respect has switched and preferred Postgres with a strong passion. It's not "sexy" but it's considered "better".

2) Stimulus.js - This was definitely the biggest and wildest choice to make. Stimulus is a Javascript framework by my old friend Sam Stephenson (Prototype.js, rbenv, turbolinks) and DHH, and it is a sort of radical declaration that your Javascript in the browser can be both powerful and modern AND simple. It leans heavily on the belief that HTML-is-good and that data-* attributes are good. It focuses on the actions and interactions and not on the rendering aspects. It took me a while to wrap my head around, and I still have to remind myself, that server-side-HTML is how you solve many problems with this stack, and avoid trying to re-render things just in the browser. So far, I'm happy with this choice, but it is definitely a radical departure from the current trends.