Discover the highlights: Scalar Conference 2024

Maria Kucharczyk

23 Apr 2024.10 minutes read

Discover the highlights: Scalar Conference 2024 webp image

Held annually in Warsaw, Poland, Scalar has established itself as THE place to be for Scala enthusiasts, software engineers, and technology leaders. This year's Scalar Conference was particularly special as we celebrated two major milestones:

  • the 20th anniversary of the Scala programming language
  • and the 10th birthday of the Scalar Conference

Given these opportunity we instantly chose #scalaversary as the theme for this year's Scalar. The idea was to celebrate the Scala programming language and its expansive ecosystem throughout the year and throw a huge Scala Fiesta at Scalar.

Here are highlights and memorable moments from Scalar 2024! 🎉

Get a glimpse of Scalar dynamic

Since 2014, when organizing the Scalar Conference, our primary goal has been to create a vibrant platform where Scala enthusiasts can connect and interact. Catch some of the coolest moments from our annual Scala fest in this aftermovie ⤵️

The Scalar Conference is all about creating a welcoming space where everyone, from expert engineers to those just starting out, can learn and grow. For Scalar 2024, we've planned a blend of insightful technical talks, hands-on workshops, and vibrant networking events, including relaxed pre- and after-parties. This way, every attendee gained new knowledge, skills, and connections.

The conference began with engaging hands-on workshop sessions led by Zainab Ali and Daniel Ciocîrlan. Participants explored and gained proficiency in using either Cats or ZIO stacks, enhancing their skill sets. Over two days, we welcomed 24 speakers who shared their insights and the latest developments in Scala!

Scalar 2024 personal highlights from our team

Adam Warski
Scala at 20 - Martin Odersky

Martin started by covering some of the history behind Scala’s development but quickly turned to looking into the future, asking the basic question: will Scala still be relevant 20 years from now? Especially in an LLM-rich world that’s coming, our shared intuition is that statically typed and verified languages will play an increasingly important role.
As for the more immediate future, Martin spoke about the work that’s going on with project Caprese: adding capabilities and capture checking to the language, as well as hinted as to what “Lean Scala” might be in his vision. While recognizing the problem that there are too many ways to write Scala, the approach focuses on simplicity. As always, exciting times in Scala-land!

Michał Ostruszka
How slow is your tram by Michał Pawlik
Well-crafted and well-delivered talk. I really enjoyed this one because the problem itself was born from “nerdy needs” which we all like (monitoring public transportation stats, delays, etc., in Wrocław). It also showed how easy and fun it is to build side projects with Scala, how good the Scala ecosystem is and that you can use it in real-world scenarios. I’m personally leaning more towards the Typelevel stack, so it was good to see some nice bits of CE, fs2, etc., code in well-delivered talk.

Contravariance: intuition building and examples by Sophie Collard
Variance, covariance, and contravariance are topics that come back every now and then in every Scala developer’s life. Some try to work it around by randomly throwing magic characters here and there. Some decide to spend “ages” studying it. I’ve been there and seen many different approaches to explaining these concepts, although this one was by far the easiest to grasp and remember. By going through a quite popular use case (vet clinic) Sophie explained the way she was approaching variance issues to first understand what and why is required and only then making informative actions in the code.

Structured Concurrency in Direct Style with Gears by Cao Nguyen Pham
It was the speaker's debut talk, and I must say it went really well. The passion, optimism, and joy while delivering the talk were great to see. I hadn't looked into Gears much before, I only knew a thing or two about it, covering similar ground to Ox by our own Adam Warski. Gears building on the so-called direct-style shows how the future of Scala can look like. The examples shown and their explanations were very informative, and I put Gears on my list of tools to look at after the conference, which I believe was the goal for the talk.

Turbocharging web socket integration for Tapir by Kamil Kloch
I first saw Kamil’s talk during the previous Scalar edition, and I was amazed by both content and the way the talk was delivered so I had pretty high expectations that obviously were well met. There was a lot of “meat” in the talk about the internals of Tapir and the way it handles websockets, but also about the way such performance tests should be done. While it was quite low-level stuff it was really interesting to see how they approached the problem and how it was ultimately solved yielding really good results.

Sounds of Scala.js by Paul Matthews
I must admit I’m not a big fan of scala.js, but being a music enthusiast and knowing the musical background of the speaker, I couldn’t miss that one. It was really great to see programmers' approach to sound synthesis, both with scala.js and in general, and that it’s not rocket science at all. Well delivered and enhanced by in-browser examples of generating music live, showing what modern browsers are capable of these days. I guess I wasn’t the only one being impressed/inspired by the talk as I saw some people building on this concept in the wild recently.

Adam Rybicki
How Slow is Your Tram by Michał Pawlik
Michał Pawlik delivers something that I'm missing from most of the conference and meetup talks by diving into practical applications of Scala for solving real-world problems. He demonstrates how Scala can be leveraged to address specific challenges, and very well known, Wrocław's public transport issues, providing actionable insights for developers. This presentation is particularly valuable for its focus on practical solutions and using Scala to solve issues.

Growing Oxen: Channel Operators and Retries by Jacek Kunicki
Jacek Kunicki’s live coding session proved to be exceptionally captivating. He tackled a tricky problem, broke it down, and, in the end, made everything "click" for me. He walked through how channel operations work under the hood, turning what could be a head-scratcher into something you can get your head around. This session deep dove into how things work behind the scenes, which helped me understand how certain concepts work.

Jacek Centkowski
The Debatably Free Monad by Nicolas Rinaudo
Nicolas Rinaudo explores the Free Monad concept, using it to develop a simple Domain-Specific Language (DSL) for a command-line interface. This interface greets users by name. It should be designed so its interpreter can be easily swapped without altering the core processing logic. He begins with a straightforward, ADT-based approach, highlighting its limitations and progressively guides us towards a refined, Free Monad-based implementation. Although the topic is complex, Nicolas presents it in an engaging and accessible^ manner.

^Your brain will hurt at times (mine did 😂)! I plan to revisit this presentation. It's packed with critical turning points, and I want to make sure that I fully understand the reasoning behind them.

Beyond the technical sessions

Between day one and day two we threw an epic After Party! Everybody enjoyed a pleasant evening filled with food, drinks, and bowling - everything you need for a great night out. The highlight was Scala's birthday cake! Here’s to the awesome years ahead of Scala!

Read the Lean Scala article by Martin Odersky


Grab some tips on how to maximize your experience at Scalar:

  • Scalar is a two-day event, with an optional extra day for workshops. While it may seem lengthy, time flies! Although talks will be available on YouTube later, the real opportunity lies in live networking. Don't spend all your time in talks; mingling with others who are using Scala in innovative ways can be incredibly enriching and informative.
  • Don't miss the afterparty! It's a fantastic opportunity to unwind in a relaxed atmosphere where people are open and friendly.
  • Spend some time discovering the city that you travelled to for Scalar! Ask us, the organisers, for some tips on attractions, museums, restaurants and other Warsaw highlights.

Scalar 2024 resources

Scalar Photo Gallery
Explore our gallery and share your favorite moments! Don't forget to tag us using #ScalarConf on social media. We'd love to see your perspectives!

Scalar 2024 playlist
Make sure to bookmark this link, we’ll be adding all the talks from Scalar 2024 to this playlist.

My Scala Story series
Discover personal stories from the Scala community in our ongoing series. The series continues to thrive with new contributions! If you know someone who should be featured, please suggest them by emailing me at

Scalar 2024 testimonials

We conducted a survey of our attendees, and the feedback has been insightful and heartwarming. A big shout-out to all the Scalarians for your responses! Here’s a glimpse of what you shared with us.

Most people in the room were probably smarter than me, so I was able to learn a lot and had enlightening discussions with people I didn't know before, and prominent members of the Scala community.

A lot of diversity in the talks.

Great buffet at the aftershow party; good mix of talks with practical applications, advanced or theoretical concepts; well organized.

Scalar 2024 was perfect in size, scope, and everything going on around it. I love it when there is only a single track so I don't miss anything due to conflicts or switching rooms. The quizzes and games sprinkled into breaks were refreshing, and almost all speakers did an amazing job to stay within time limits. I've been to many conferences, and this is definitely one of the best.

Also, we are thrilled by the enthusiastic response from our community who attended the recent Scalar conference! A big thank you to everyone who took the time to share their highlights on social media. Catch a glimpse of what made Scalar such a memorable event through the eyes of our attendees!

As the organisers we’d like to thank you our Sponsors for your generous support of this year's Scalar Conference. Your contribution enabled us to host a platform where Scala enthusiasts can connect, share, and innovate together.

Scalar Conference

Why to attend as a software developer?

Scalar is an enriching experience for anyone interested in Scala:

  • join technical talks and hands-on workshops led by experts in Scala, it’s an opportunity to learn new skills or deepening existing knowledge;
  • mingle with other Scala enthusiasts and industry leaders, make valuable connections, potential collaborations, or even land job opportunities;
  • become part of the Scala community and get to know individuals who are passionate about Scala same as you are;
  • learn insights that are crucial for staying competitive in the field;
  • get inspiration for your own projects and ideas using networking opportunities the conference offers.

Scalar is committed to diversity and inclusivity, offering Diversity Tickets to ensure that everyone interested can participate, regardless of their background.

Why to attend as a brand?

Scalar is a platform that brings the Scala community closer together since 2014. By sponsoring future Scalar conferences, your brand gains significant visibility among this vibrant group. Attending Scalar is an excellent opportunity to showcase your expertise or tools, engage directly with engineering professionals, and attract the top talent your company needs.

Join Scalar 2025

This year, celebrating Scala’s 20th birthday, was a spectacular showcase of the thriving Scala community. Now, our excitement builds for the next Scalar conference in 2025. We look forward to welcoming you there!

Save the date: March 27-28, 2025!

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