Elixir - The next big language for the web

In this article I will explain why I think the Elixir language will make a big impact in the world of web development.

From obscurity to the default choice

First a short tale of another language that went from being largely unknown to very well known:

In 2003 I started using Ruby. A classmate from university was about to release a web framework for it. You could write software with much fewer lines of code than in Java. The combination of Ruby and this new web framework felt so much better for web development than what I had been using before - PHP.

So when a client wanted to redo an e-commerce site, I convinced them to rewrite it in Ruby and use this new framework that was now called Rails. Ever since I have been programming Ruby professionally.

Back then you could look at the download graphs of Rails and Ruby and it was obvious that Rails was driving downloads of Ruby. Rails took Ruby out of obscurity and some years later even many non-programmers had heard about this web framework.

It was very interesting to see how quickly Rails went from being used by a handful of people to being the “it-framework” and the default choice for startups that needed web based software. And some of them are now traded on the stock market with market caps in the billions of dollars.

One of them is Twitter. In 2009 Twitter had been experiencing a tremendous growth of users and traffic. They decided to change core parts of their infrastructure from Ruby to Scala. The way Scala handles concurrency made it easier for Twitter to handle the growth.

Erlang

There is another language that is both functional and has an even longer history of handling massive concurrency: Erlang. It was made at Ericsson in the 1980s to allow for better development of telephony applications.

If you use 4G data on your phone it is more likely than not that the data is going through equipment from Ericsson. And it runs Erlang. Have you ever thought about how phone operators do not disconnect everyone’s phone calls in order to apply software updates? Erlang is made to allow phone switch system to run continuously and supports hotswapping: software updates while the software is running.

Whatsapp have hundreds of millions of users. On most other platforms handling more than ten thousand concurrent connections on one machine is seen as challenging, but Whatsapp have individual servers with more than 2 million concurrent connections. 2 million connections on a single server, handled by Erlang.

Erlang is also popular for game servers. Millions of users play multiplayer games with game server infrastructure handled by Erlang for titles such as Call of Duty and Game of War.

The Erlang platform has many advantages for serving reliable, scalable internet applications, it has a proven track record and has been around for decades. So why is it not a more popular choice for web development?

I think part of it is that with Erlang it is not as easy to get up and running with a new website. I do not think it is because the language is very hard to learn - it is not, but often people will take the path of least resistance. The Erlang syntax looks a bit strange if you are used to looking at languages such as C, Java, JavaScript, PHP, Ruby, Perl etc. And things like package management, build tools, meta-programming, unicode handling and web frameworks are not as straight forward as in languages such as Ruby.

Elixir

But those areas are all addressed in Elixir. Elixir creator José Valim said: “I liked everything I saw in Erlang, but I hated the things that I didn’t see”. Elixir has its own package management system, macros, an easy to use build tool and unicode handling.

Elixir is a language that runs on the Erlang VM. So it has all of the benefits of the mature, battle proven system and you can use the existing Erlang libraries with no performance penalty. And Elixir adds a bunch of niceties. One of them is the pipe operator.

The difference between Erlang and Elixir is not just the syntax. But syntax does matter, and especially for Ruby developers the Elixir syntax will be very familiar.

Immutability and functional programming

Elixir is a functional language with immutability.

After having worked with immutable data for a while, I have realized how beneficial it is. Even for single threaded programming, mutability brings an uncertainty about how a program will execute. And I do not miss the mutability at all. Functional programming and immutability helps to clarify things and makes it easier to reason about code.

Concurrency

Another strong point for Elixir is concurrency. Concurrency is here to stay, for several reasons. To mention a few: The trend in hardware is more and more CPU cores. The CPU manufacturers are not going to improve single core performance at the same rate as before. Instead they are adding more cores. Also the world is concurrent and you do not want end users or other software services to needlessly wait for a response because your single threaded software is busy.

In most languages concurrency is a bit of a pain. Not only is it dangerous and hard to do synchronization. With mutable state and forking of native processes it is also often slow and uses a lot of memory.

Doing concurrency in Erlang or Elixir versus other languages is a bit like doing branches in Git vs Subversion. In subversion it was very complicated to do - and I never did it. In Git it is a lot easier and I do it all the time.

In Elixir it is very easy to create a new process and it performs very well, so if the situation calls for it, it is straightforward to do. It is an integral part of the platform and does not require a separate library. Note that Erlang/Elixir processes are not native processes, they are much more light weight and are scheduled by the Erlang BEAM virtual machine.

Web framework

Phoenix is the most popular web framework for Elixir right now. The creator of Elixir is a Rails core member and the creator of Phoenix also has a background of working with Rails. While there is no desire to simply recreate Rails in Elixir, it means that Phoenix is also relatively easy to get started with because Rails has set certain minimum standards in that regard.

One of the most exciting features is the real time capabilities with channels between javascript on the client and Elixir on any of the servers in the cluster. Each single visitor to a website can have its own process on the server and its own real time connection. This opens up possibilities that are not present in traditional web frameworks.

By the way, seeing μs (the microsecond symbol) in web server logs because of sub 1ms response times is quite nice ;) Efficiency and speed are important for the end user experience, and also means less waste of energy and money on servers.

Programmer happiness and beautiful code

There are other languages that are faster than Ruby, but there are still good reasons to use for instance Ruby over Java: it is a nice language to work with and you can relatively quickly write concise code. Maybe Java code could perform better, but in many cases the Java code would not be as fun or quick to write, nor as easily maintainable. So the argument of just buying more powerful servers to make up for it can be a reasonable tradeoff in some cases. But what if you did not have to make such a choice?

With Elixir I do not feel like I trade any joy or speed of development for the performance, reliability and concurrency benefits of the Erlang VM. Elixir provides all of the Erlang benefits such as performance and reliability without giving up the productivity benefits of Ruby.

Déjà vu

Like with Ruby 12 years ago, once again I feel that this new platform is so much better than the other solutions. And it is not just a gut feeling, there are rational arguments to back it up. Another similarity is that Dave Thomas is also excited about Elixir and has written a book about the language.

It is as if everything is aligned for Elixir to be the next new big thing for web development. In the last 10 years Ruby and Python have been popular choices for the web. I think it is likely that in a few years Elixir instead will be the go-to language for new web projects.