Matej Cerny
@matejcerny.bsky.social
Functional programming enthusiast with strong foundations in the relational databases world #FP #Scala #Postgres
With #Scala 3.8 around the corner, let's recap its biggest changes:
1️⃣ JDK 17 as a minimum version
2️⃣ "Better fors" (SIP-62)
3️⃣ Standard library built with Scala 3
1️⃣ JDK 17 as a minimum version
2️⃣ "Better fors" (SIP-62)
3️⃣ Standard library built with Scala 3
November 13, 2025 at 7:00 AM
With #Scala 3.8 around the corner, let's recap its biggest changes:
1️⃣ JDK 17 as a minimum version
2️⃣ "Better fors" (SIP-62)
3️⃣ Standard library built with Scala 3
1️⃣ JDK 17 as a minimum version
2️⃣ "Better fors" (SIP-62)
3️⃣ Standard library built with Scala 3
The biggest improvements in #Scala 3 are not enums or nicer implicits syntax, but:
🤝 Making binary compatibility across versions possible (via TASTy)
⚡ A built-in interactive compiler (instead of a batch tool)
🔗 A modular architecture that makes new features easier to add
🤝 Making binary compatibility across versions possible (via TASTy)
⚡ A built-in interactive compiler (instead of a batch tool)
🔗 A modular architecture that makes new features easier to add
November 12, 2025 at 12:37 PM
The biggest improvements in #Scala 3 are not enums or nicer implicits syntax, but:
🤝 Making binary compatibility across versions possible (via TASTy)
⚡ A built-in interactive compiler (instead of a batch tool)
🔗 A modular architecture that makes new features easier to add
🤝 Making binary compatibility across versions possible (via TASTy)
⚡ A built-in interactive compiler (instead of a batch tool)
🔗 A modular architecture that makes new features easier to add
🎉 Scala 3.7.4 is officially out, bringing several fixes and backports. See the full changelog 👇 #scala github.com/scala/scala3...
Release 3.7.4 · scala/scala3 · GitHub
Highlights of the release
Bump Scala CLI to v1.9.1 (was v1.9.0) #23962
Make coverage more similar to the one in Scala 2 #23722
Deprecations for removal
Deprecate scala_legacy/MainGenericRunner/s...
github.com
November 11, 2025 at 3:28 PM
🎉 Scala 3.7.4 is officially out, bringing several fixes and backports. See the full changelog 👇 #scala github.com/scala/scala3...
Streams are a powerful tool for control flow, covering topics such as event handling, file processing, reading from the database... Learn more from Zainab Ali's talk at the London Scala User Group. #scala youtu.be/XMmzoJBtC_Q
LSUG Aug 2025 Zainab Ali - Taking the plunge: a deep dive into streaming with fs2
youtu.be
November 7, 2025 at 2:53 PM
Streams are a powerful tool for control flow, covering topics such as event handling, file processing, reading from the database... Learn more from Zainab Ali's talk at the London Scala User Group. #scala youtu.be/XMmzoJBtC_Q
Please share so my boss Michal is happy! 😂 Or to spread the word about VirtusLab / SoftwareMill's new podcast! 📢 Or to support local #Scala agencies! 💪 www.youtube.com/watch?v=dcYZ...
Beyond the Commit, Episode 1: Michal Janoušek
www.youtube.com
November 5, 2025 at 2:30 PM
Please share so my boss Michal is happy! 😂 Or to spread the word about VirtusLab / SoftwareMill's new podcast! 📢 Or to support local #Scala agencies! 💪 www.youtube.com/watch?v=dcYZ...
There are so many great thoughts, to pinpoint just a few:
1️⃣ Tooling is nowhere near other languages
2️⃣ Missing a true "Spring Boot-like" framework
3️⃣ Official docs need real-world examples
4️⃣ The persistent misconception that "you need async for performance"
#scala youtu.be/a-uME7QBlxg
1️⃣ Tooling is nowhere near other languages
2️⃣ Missing a true "Spring Boot-like" framework
3️⃣ Official docs need real-world examples
4️⃣ The persistent misconception that "you need async for performance"
#scala youtu.be/a-uME7QBlxg
YouTube
Haoyi Li is a software engineer and a core contributor to the Scala ecosystem. He's built a whole suite of Scala libraries under the com.lihaoyi banner, focusing on simplicity and productivity, as well as the Mill build tool, which he has since expanded beyond Scala to support other JVM tools like Java and Kotlin and experimental support for other things like TypeScript and Android, and promises better performance and user friendliness than Gradle and Maven can ever match. He's also the author of the book Hands-on Scala Programming, which focuses on getting things done with Scala.
My own course, Scala Projects, uses Haoyi's book examples as starting points for full-fledged, shippable projects that you can use for yourself or turn into products:
https://rockthejvm.com/courses/scala-projects
Timeline
0:00 Intro
1:08 Conference tour
8:20 Haoyi's work on Mill
13:55 What Mill does better than other tools
18:48 Picking a config language
21:53 Scala at scale at Databricks
29:20 How Scala can continue innovating
34:50 Increasing industry adoption of Scala
39:45 Misconceptions about Scala
42:39 Haoyi's experience switching between IC - tech lead - manager - IC
49:39 How Haoyi started programming and why Scala stood out
57:08 Scala differentiators for the future
1:01:05 How Haoyi maintains his OSS library ecosystem
1:06:43 Hands-On Scala Programming: writing, publishing, open-sourcing
1:14:40 Haoyi's current and future contributions to Scala
1:18:16 Discussion on AI agents
1:29:54 Parting thoughts
youtu.be
November 5, 2025 at 6:05 AM
There are so many great thoughts, to pinpoint just a few:
1️⃣ Tooling is nowhere near other languages
2️⃣ Missing a true "Spring Boot-like" framework
3️⃣ Official docs need real-world examples
4️⃣ The persistent misconception that "you need async for performance"
#scala youtu.be/a-uME7QBlxg
1️⃣ Tooling is nowhere near other languages
2️⃣ Missing a true "Spring Boot-like" framework
3️⃣ Official docs need real-world examples
4️⃣ The persistent misconception that "you need async for performance"
#scala youtu.be/a-uME7QBlxg
This is probably the most complete tutorial on typeclasses in Scala 3, it's basically a short book. Bookmark it, as it has everything: givens, derivation, mirrors, inline defs, macros... you name it. #scala kubuszok.com//2025/sanely...
November 4, 2025 at 7:46 PM
This is probably the most complete tutorial on typeclasses in Scala 3, it's basically a short book. Bookmark it, as it has everything: givens, derivation, mirrors, inline defs, macros... you name it. #scala kubuszok.com//2025/sanely...
After years, I came to the same conclusion: it's worth taking the time to use proper test data, even for attributes you don't currently use in your business logic. It'll save you so much time later. etorreborre.blog/dont-look-do...
Don't look down! Look at the data instead!
You might get the same vertigo
etorreborre.blog
November 4, 2025 at 3:53 PM
After years, I came to the same conclusion: it's worth taking the time to use proper test data, even for attributes you don't currently use in your business logic. It'll save you so much time later. etorreborre.blog/dont-look-do...
The tech industry is creating its own talent crisis. By ditching junior devs for AI hype, companies are just burning out their seniors and killing the future talent pipeline. #ai www.youtube.com/watch?v=DcJ5...
Dev will really suck in a few years...
www.youtube.com
November 3, 2025 at 3:53 PM
The tech industry is creating its own talent crisis. By ditching junior devs for AI hype, companies are just burning out their seniors and killing the future talent pipeline. #ai www.youtube.com/watch?v=DcJ5...
Binary compatibility is a very important topic that every senior should understand. This video, even though it's about Smithy4s, explains concepts for evolving a library's schema in a binary-compatible way. #scala youtu.be/1HFV-tGZVlY
Deep dive: how I added THIS feature to smithy4s (bincompat-friendly mode)
youtu.be
November 2, 2025 at 10:40 AM
Binary compatibility is a very important topic that every senior should understand. This video, even though it's about Smithy4s, explains concepts for evolving a library's schema in a binary-compatible way. #scala youtu.be/1HFV-tGZVlY
The most comprehensive collection of Scala learning material finally on YouTube. A freaking 283 videos! #scala www.youtube.com/@Ziverge/pla...
October 31, 2025 at 3:40 PM
The most comprehensive collection of Scala learning material finally on YouTube. A freaking 283 videos! #scala www.youtube.com/@Ziverge/pla...
Respect to Dylan Halperin for his massive contribution to @http4s! 🚀 His new MultipartReceiver is in the latest version after over a year of review, adding safer, fail-fast file uploads with size limits and no buffering. #scala github.com/http4s/http4...
Release v0.23.33 · http4s/http4s · GitHub
What's Changed
http4s-core
fix: proxy authorization header instantiation with basic credentials by @tpetillot in #7742
Introduce MultipartReceiver for custom, fail-fast multipart decoding by @dyle...
github.com
October 31, 2025 at 7:29 AM
Respect to Dylan Halperin for his massive contribution to @http4s! 🚀 His new MultipartReceiver is in the latest version after over a year of review, adding safer, fail-fast file uploads with size limits and no buffering. #scala github.com/http4s/http4...
I was really looking forward to io_uring in Postgres 18, but it turns out it's not the winning I/O strategy. Worker, the new default, seems to be the best all-around method so far, performing well on all storage types. #postgres planetscale.com/blog/benchma...
Benchmarking Postgres 17 vs 18 — PlanetScale
Postgres 18 brings a significant improvement to read performance via async I/O and I/O worker threads. Here we compare its performance to Postgres 17.
planetscale.com
October 30, 2025 at 7:42 PM
I was really looking forward to io_uring in Postgres 18, but it turns out it's not the winning I/O strategy. Worker, the new default, seems to be the best all-around method so far, performing well on all storage types. #postgres planetscale.com/blog/benchma...
Java is removing sun.misc.Unsafe, an API which is widely used but was never supported or meant to be public. This is one of the reasons for the adoption of JDK 17 in the upcoming version of Scala, which relies on Unsafe for its lazy val implementation. #java #scala youtu.be/jCbqkMKegmY
JEP Explained. JEP 471: Deprecate the Memory-Access Methods in sun.misc.Unsafe for Removal
YouTube video by IntelliJ IDEA, a JetBrains IDE
youtu.be
October 29, 2025 at 7:43 PM
Java is removing sun.misc.Unsafe, an API which is widely used but was never supported or meant to be public. This is one of the reasons for the adoption of JDK 17 in the upcoming version of Scala, which relies on Unsafe for its lazy val implementation. #java #scala youtu.be/jCbqkMKegmY
Match types, an awesome feature which I haven't properly used yet 😀 #scala alexn.org/blog/2025/10...
Scala 3 / Match Types - Alexandru Nedelcu
Scala has a neat new feature, resembling TypeScript’s “conditional types”, but more powerful.
alexn.org
October 28, 2025 at 7:39 AM
Match types, an awesome feature which I haven't properly used yet 😀 #scala alexn.org/blog/2025/10...
Taking bets on when Spark will adopt Scala 3. Just by reading the PR, my guess is never. 😔 #scala #spark github.com/apache/spark...
Enable -Xsource:3 compiler flag by joan38 · Pull Request #50474 · apache/spark · GitHub
What changes were proposed in this pull request?
Enable -Xsource:3-cross compiler flag for future migration to Scala 3.
https://docs.scala-lang.org/scala3/guides/migration/tooling-scala2-xsource3....
github.com
October 27, 2025 at 9:59 AM
Taking bets on when Spark will adopt Scala 3. Just by reading the PR, my guess is never. 😔 #scala #spark github.com/apache/spark...
Behold! The mythical Scala.js job offer is real! www.reddit.com/r/scala/comm... #scala
Reddit - The heart of the internet
www.reddit.com
October 24, 2025 at 1:33 PM
Behold! The mythical Scala.js job offer is real! www.reddit.com/r/scala/comm... #scala
If you are able to represent an illegal state in your code, you should rethink your model. Start with these two simple tips 👇 www.yannmoisan.com/make-illegal... #ddd #scala
October 22, 2025 at 6:58 PM
If you are able to represent an illegal state in your code, you should rethink your model. Start with these two simple tips 👇 www.yannmoisan.com/make-illegal... #ddd #scala
Scala 3 would obviously also go in the S tier. #scala youtu.be/7EttvdzxY6M
Ranking Enums in Programming Languages
youtu.be
October 22, 2025 at 6:46 AM
Scala 3 would obviously also go in the S tier. #scala youtu.be/7EttvdzxY6M
The first Trezor with a custom-built secure element is out! What a piece of tech - Bluetooth, a special LiFePO battery with Qi2 charging, a display with 520x380 resolution, an aluminium body and an IP54 rating 🤯 #bitcoin trezor.io/trezor-safe-...
Trezor Safe 7 | Bitcoin-only Hardware Wallet With TROPIC01 Chip
Secure your bitcoin with Trezor Safe 7—Bluetooth, high-res color touchscreen & quantum-ready security.
trezor.io
October 21, 2025 at 11:10 AM
The first Trezor with a custom-built secure element is out! What a piece of tech - Bluetooth, a special LiFePO battery with Qi2 charging, a display with 520x380 resolution, an aluminium body and an IP54 rating 🤯 #bitcoin trezor.io/trezor-safe-...
🎉 Scala 3.3.7 was quietly released last week with a backported fix for Android development, improved coverage reports, hashcodes of enums, and more. #scala github.com/scala/scala3...
Release 3.3.7 · scala/scala3 · GitHub
Highlights of the release
Warn a standard interpolator used toString on a reference type with -Wtostring-interpolated #20578
Unblock Scala 3 on Android #22632
Implement :jar (deprecate :require) i...
github.com
October 21, 2025 at 6:22 AM
🎉 Scala 3.3.7 was quietly released last week with a backported fix for Android development, improved coverage reports, hashcodes of enums, and more. #scala github.com/scala/scala3...
Why use a dedicated k8s operator setup when you can spend two days building your own webhook-based version in Scala? 😂 Anyway, it was a great read! #scala blog.indoorvivants.com/2025-10-20-r...
October 20, 2025 at 8:34 PM
Why use a dedicated k8s operator setup when you can spend two days building your own webhook-based version in Scala? 😂 Anyway, it was a great read! #scala blog.indoorvivants.com/2025-10-20-r...
What a day to have my first on-call shift 😀 #awsoutage
October 20, 2025 at 9:06 AM
What a day to have my first on-call shift 😀 #awsoutage