What is Clojure South?
According to the official website:
"Organized by Nubank, Clojure South is part of the official Clojure community schedule, connecting developers, enthusiasts, and companies to share real experiences, discuss trends, and strengthen the global network of the language." - Translated from Brazilian Portuguese by me.
Motivation
In a conversation with a Brazilian woman I met at Lambda Days 2025 (I talked about what it was like to attend this event in this article), I asked if she would attend the conference (she works at Nubank) and found out she would be an instructor for the Clojure workshop. During this conversation, she suggested that I should submit a talk proposal. I mentioned an idea I had in mind but was feeling a bit insecure about sending it. She encouraged me to try, and I decided to take a chance!
Although I already have some talks on my resume, I felt that maybe I should be more cautious in this case, and submit a proposal for a lightning talk (a 10-minute talk with no time for questions).
A few weeks later, to my surprise, the proposal was accepted!
Theme
I had two possible topics in mind. One about teaching Clojure and Functional Programming to beginners (because of my course Clojure: Introdução à Programação Funcional; an Introduction to Functional Programming through Clojure, for Brazilians). And another about a project I built at the company where I work, using Clojure in the backend and the programming language Elm for the front-end.
I chose the second one. It was already a project I wanted to talk about publicly, and this seemed like a great opportunity!
Another factor is that the project is related to a very well-known App in Brazil, the Digital Driver's License — an App developed by SERPRO and available for Android and iOS. I imagined this could increase the chances of the talk being accepted.
The full description I submitted was:
During the development of the Carteira Digital de Trânsito (Digital Driver's License), I realized how challenging it was to support an App with millions of users integrated with many systems. I dreamed of creating a simple, friendly internal interface for queries that would make support easier. That’s how Apoio CDT was born, a web system that automated processes and enabled fast and secure queries. With a Clojure backend and an Elm front-end, we developed an MVP in three weeks. The result was a simple, efficient, and easy-to-maintain web architecture over the years.
As far as I know, this was the company’s first project using Clojure and also the first using Elm. And it was the first time I had the opportunity to talk about this system to people outside the company where I work!
Other Talks and Workshops
The event lasted two days, and the first day featured the two workshops:
Clojure Workshop
An introductory Clojure course, in English, taught by Christoph Neumann, Clojure Developer Advocate at Nubank.
Although I already have experience with Clojure, it was great to reinforce the main concepts of the language and I even learned some fundamentals I didn’t know yet!
Datomic Workshop
The afternoon of the first day was dedicated to the workshop of the Datomic database. It was taught in Brazilian Portuguese by Carolina Silva (the same one I mentioned at the beginning of this article) and Hanna Figueiredo, both Software Engineers at Nubank.
I had already watched several talks about Datomic and always found it an intriguing and interesting database. I believe it would make a lot of sense to use it in several projects I have worked on or currently work on.
The workshop covered many theoretical concepts of Datomic, but it was also very hands-on.
You can check out the hands-on portion of the workshop in this GitHub repository!
I confess it was a lot of information in a short time. I will definitely need to revisit the repository and practice a lot more to internalize the core concepts of this database. But it was totally worth it!
If before I already thought studying this database was worthwhile, now I’m certain of it!
Conversations and Feedback
Right when I arrived at the event, I had the chance to talk to some people I only knew online, such as Arthur Fücher. Besides being a Senior Software Engineer at Nubank, Arthur is very active in the Brazilian Clojure community!
And even though I am quite shy, I was able to meet many great people from Brazil and other countries.
In particular, I was welcomed very warmly by Christoph Neumann. I was standing quietly in a corner during the happy hour, after the second day of the event, eating and thinking about heading home, when he approached me and started a conversation. We talked a bit, and I began asking a few questions about Datomic. During the conversation, I mentioned that Datomic might be a good fit for the company where I work. When I said what the company does, he became very interested! And soon offered to introduce me to Joe Lane, Principal Engineer Building Datomic at Nubank!
I talked to Joe and, again, was very kindly received! He seemed genuinely excited when I mentioned where I worked and the types of projects SERPRO develops, and he offered to answer any questions about Datomic — even mentioning that SERPRO could be a great Datomic case study.
During the event, I also had the opportunity to meet people who took my Clojure course! Among them, I met Bruno Guimarães, currently a Senior Software Engineer at Nubank and the host of the conference.
Meeting students of my online course in person is always a very special experience! The numbers, the stats, the comments — they gain a face, a voice, life. It's truly rewarding!
On the second day, after my talk, many people came to talk and learn more about how I introduced Clojure into a federal government system in Brazil. Some had specific questions about my motivation for using Elm on the front-end (instead of opting for ClojureScript), plus several other interesting conversations.
The feedback was very positive, and all the conversations were friendly, fun, and respectful.
Food (and More Conversations)
The event had a welcome coffee in the morning and coffee breaks throughout the day. The quality was excellent and everything was quite formal (maybe a bit too formal? lol).
For lunch, there were several options (not included in the ticket price) within the same building complex where Nubank Sparks is located. This made things much easier, especially on the workshop day, since I had my laptop with me.
You could eat wherever you wanted. But I liked the nearby options, and it became yet another opportunity to talk to more people from the event. Again, even being shy and sitting somewhere more secluded, several people soon came to sit with me and chat. At that moment, I met a Ukrainian attendee who showed us the Diia App, where she can have digital versions of several documents such as her Driver’s License, Passport, and more — with access to over 130 government services (you can learn more about this App on its Wikipedia page)!
Was It Worth It?
Definitely, yes!
The event happened on two weekdays (a Monday and Tuesday). This may make it difficult for some people to attend — for example, a colleague of mine couldn’t go because his company didn’t allow him to take those days off. But for those who can attend, it’s far less tiring than having an event like this over the weekend after a long workweek.
I had purchased the early-bird tickets before my talk was accepted, but later the event organizers refunded me — I received free tickets for both days as a speaker. They also offered help with transportation and lodging, which I declined since the event was close to where I live.
The experience of speaking at an event of this magnitude, even if only for 10 minutes, was incredible! It’s a feeling of great gratitude to the people who organized the conference and who trusted in my potential!
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