The inaugural Code BEAM Lite London conference was held at CodeNode last month, featuring 10 talks, 80 attendees, and an Erlang Solutions booth. There, attendees had the chance to set a high score in a BEAM-based asteroid game created by ESL’s Hernán Rivas Acosta, and win an Atari replica.

Learning from and networking with experts across the BEAM world was an exciting opportunity. Here are the highlights from the talks at the event.

Keynote: Gleam’s First Year

Louis Pilfold kicked things off with an opening keynote all about Gleam, the statically-typed BEAM language he designed and developed, and which announced its version 1.0 a year ago at FOSDEM in Brussels. 

Louis laid out the primary goals of v1: productivity and sustainability, avoiding breaking changes and language bloat, and extensive, helpful, and easily navigable documentation. He then walked us through some of the progress made on Gleam in its first year of official release, with a particular focus on the many convenience and quality-of-life features of the language server, written in Rust. Finally, he measured Gleam’s success throughout 2024 in terms of Github usage and sponsorship money and looked forward to his goals for the language in 2025.

The Art of Writing Beautiful Code

“Make it work, then make it beautiful, then if you really, really have to, make it fast. 90 per cent of the time, if you make it beautiful, it will already be fast. So really, just make it beautiful!” Most of us are likely familiar with this famous Joe Armstrong quote, but what does it actually mean to write beautiful code? 

This question was the focus of Brujo Benavides’ talk, a tour through various examples of “ugly” code in Erlang, some of which may well be considered beautiful by programmers trying to avoid repeating code. If beauty is in the eye of the beholder, what’s more important is that each project has a consistent definition of what “beautiful” means. Brujo explored different methods of achieving this consistency, and how to balance it with the need for fast commits of important changes in a project.

Why Livebook is My Dream Data Science Workbench

Amplified’s Christopher Grainger took a more cerebral approach to his talk on Livebook, drawing on his background as both a historian and a data scientist to link the collaborative notebook software to a tradition of scientific collaboration dating back thousands of years. 

In his view, the fragmentation of the digital age led to key components of this tradition being lost; he explored how LiveBook’s BEAM architecture brings it closer to being a digital equivalent of real-time collaboration in a lab than prior technologies like Jupyter Notebooks, and what further steps could be taken to get even closer to it in the future.

Deploying Elixir on Azure With Some Bonus Side Quests

Matteo Gheri of Pocketworks provided an industrial example of Elixir in action, explaining how his company used Azure in the course of building a Phoenix app for UK-based taxi company Veezu. 

Azure is used to host only 3.2% of Elixir apps, and Matteo walked through their journey figuring it out in detail, touching on deployment, infrastructure, CI/CD, and the challenges they encountered.

Let’s Talk About Tests

Erlang Solutions’ own Natalia Chechina took the stage next for a dive into the question of tests. She explored ways of convincing managers of the importance of testing, which types of test to prioritise depending on the circumstances of the project, and how to best structure testing in order to prevent developers from burning out, stressing the importance of both making testing a key component of the development cycle and cultivating a positive attitude towards testing.

Eat Your Greens: A Philosophy for Language Design

Replacing Guillaume Duboc’s cancelled talk on Elixir types was Peter Saxton, developer of a new language called Eat Your Greens (EYG). The philosophy behind the title refers to doing things that may be boring or unenjoyable but which lead to benefits in the long run, such as eating vegetables; Peter cited types as an example of this, and as such EYG is statically, structurally, and soundly typed. He then walked through other main features of his language, such as closure serialisation as JSON, hot code reloading, and the ability for it to be run entirely through keyboard shortcuts.

Trade-Offs Using JSON in Elixir 1.18: Wrappers vs. Erlang Libraries

Michał Muskała has a long history working with JSON on the BEAM, starting with his development of the Jason parser and generator, first released in 2017. He talked us through that history; writing Jason, turning his focus to Erlang/OTP and proposing a JSON module there, and then building on that for the Elixir JSON module, now part of the standard library in 1.18. 

He discussed the features of this new module, why it was better to use wrappers while transitioning to Elixir instead of calling Erlang directly, and how to simplify migration from Jason to JSON in advance of OTP 27 eventually being required by Elixir.

Distributed AtomVM: Let’s Create Clusters of Microcontrollers

A useless machine and a tiny, battery-free LED device played central roles in Paul Guyot’s dive into AtomVM, an Erlang- and Elixir-based virtual machine for microcontrollers. He kicked off by demonstrating La machine, the first commercial AtomVM product, albeit without an internet connection, before explaining AtomVM’s intended use in IoT devices, and the recent addition of distributed Erlang. This was backed up by another demonstration, this time of the appropriately named “2.5g of Erlang” device. Finally, he explained AtomVM’s advantages compared to other IoT VMs and identified the next steps for the project.

Erlang and RabbitMQ: The Erlang AMQP Client in Action

Katleho Kanyane from Erlang Solutions then provided another industry use case, discussing how he helped to implement a RabbitMQ publisher using the Erlang AMQP client library while working with a large fintech client. Katleho talked through some of the basics of RabbitMQ implementation, best practices, and two issues he ran into involving flow control, an overload prevention feature in RabbitMQ that throttles components and leads to drastically reduced transfer rates. He wrapped up by discussing lessons he learned from the process and laying out a few guidelines for designing a publisher.

Keynote: Introducing Tau5 – A New BEAM-Powered Live Coding Platform

The closing keynote was also the only talk of the day to kick off with a music video, though that should be expected when live coding artist and Sonic Pi creator Sam Aaron is the one delivering it. Sam spoke passionately about his goal to make programming something that everyone should be able to try without needing or wanting to become a professional and discussed his history of using Sonic Pi’s live coding software in education, including how he worked some complicated concepts such as concurrency in without confusing students or teachers.

He then discussed the limitations of Sonic Pi and how they are addressed by his new project, Tau5. While still in the proof-of-concept stage, Tau5 improves on Sonic Pi by being built on OTP from the ground up, being able to run in the browser, and including new features like visuals to add to live performances. He concluded with a demonstration of Tau5 and an explanation of his intentions for the project.

Final Thoughts

Code BEAM Lite London 2025 was a fantastic day filled with fascinating talks, cool demos, and plenty more to excite any BEAM enthusiast.

From hearing about the latest Gleam developments to diving into live coding with Tau5, it was clear that the community is thriving and full of creative energy. Whether it was learning tips for practical BEAM use or exploring cutting-edge new tools and languages, there was something for everyone.

If you missed out this time, don’t worry: you’ll be welcome at the next one, and we hope to see you there. Until then, keep building, keep experimenting, and above all keep having fun with the BEAM!