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June 22nd, 2026, ISSUE 620

READING

Kyo - Build with AI

The same type system that checks your code checks your agents.
Kyo contributors
Uni - Essential Scala Utilities

Refined for Scala 3 with minimal dependencies.
Taro L. Saito (@taroleo)
S2D Development Series - Snake, Day 1

Welcome to the first post of the S2D development series! In this series I will show you how to develop some small games step by step using my library S2D, and the first game in the list is... Snake!!
Matias Finochio
Proposal: a working group for operator-side Scala security

What I can't find is a space for the application/operator side — the people running Scala in production who want to track CVEs across their dependencies and the JVM runtime, share secure-ops practices, and compare notes. There's no security channel, no operator-facing guidance beyond a couple of docs, and no group organizing any of it.
ke7cfn

VIDEOS

IntelliJ IDEA x Scala: Make Your Tests Behave (Finally)

How to streamline your Scala testing workflow inside IntelliJ IDEA, covering everything from creating test suites to leveraging live templates. The video also dives into advanced features like debugging configurations, code coverage, and profiling to help you ensure your code behaves exactly as expected.
Maciej Gorywoda (@makingthematrix)

RELEASES

Scala 3.3.8 LTS

Support for JDK 26, multiple coverage improvement to make it on par with Scala 2 support, new @uncheckedOverride annotation, trap Ctrl-C in the REPL, numerous linting and presentation compiler improvements and fixes, and more!
Scala contributors (@scala_lang)
sbt 2.0.0

Finally, the sbt 2.0 project has been released!
Eugene Yokota (@eed3si9n)
Sage

A fast and modern Redis/Valkey client library in Scala 3, with support for ZIO, Cats Effect, Kyo and Ox. It is a RESP3 protocol-native implementation, designed with advanced use cases in mind (pipelining, cluster, caching, etc).
Pierre Ricadat (@ghostdogpr)
Scala.js 1.22.0

Harness the Scala and JavaScript ecosystems to develop robust apps for browsers, serverless, and Node.js.
Scala.js contributors (@scala_js)
vibe-types

Multi-language guide to type-safety techniques. A catalog of type-system techniques across Scala 3, Rust, Lean 4, TypeScript, and Python. One skill per language.
Juan Pablo Romero (@1jpablo1)
Mill 1.2.0 RC1

Fine-grained concurrency (no more global lock!), bazel-compatible remote caching, and many more goodies. Please try it out!
Li Haoyi (@li_haoyi)
Scalapptainer

A cross-platform Scala 3 wrapper around Apptainer. Add it to your build and drive Apptainer containers from Scala on Linux, Windows and macOS.
Oron Port
h4sbl

Enhanced logging middleware for http4s applications. It offers colorful, configurable, and comprehensive logging for HTTP operations.
Fabrizio Colonna
declinio

Seamless integration between Decline and Cats Effect without the awkward constructor syntax of Decline.
Fabrizio Colonna (@github)
dbos4s

A thin layer over the official dev.dbos:transact Java library that lets you turn vanilla Scala functions into durable workflows.
Matthieu Court

EVENTS

The Scala Workshop, Jun 29th, Brussels, Belgium

The Scala Workshop is the continuation of the Scala Symposium, providing a forum for researchers and practitioners to discuss the design, implementation, and applications of the Scala programming language. Topics include language features, compiler internals, type systems, libraries, tools, and industrial applications.
Scala Workshop
Scala Days, Oct 12th - 13th, Berlin, Germany

We are very happy to announce that the Scala Days 2026 conference will be taking place 12 - 13 October in Berlin, Germany, one of Europe’s most vibrant tech and open source hubs, known for its strong culture of collaboration and its growing role in advancing digital sovereignty through open technologies.
Scala Days (@scaladays)
J On the Beach, Oct 29th - 30th, Malaga, Spain

A Pure Tech and Fun Conference for All Things Data.
J On The Beach (@JOTBConf)
Lambda World, Oct 29th. - 30th, Malaga, Spain

Experience the sunshine, the code, and the unforgettable vibe that made Lambda World 2025 shine in Málaga.
Lambda World (@lambda_world)





  1. Scala Times Issue #620

    Kyo - Build with AI. Uni - Essential Scala Utilities. S2D Development Series - Snake, Day 1. Proposal: a working group for operator-side Scala security. IntelliJ IDEA x Scala: Make Your Tests Behave (Finally).


  2. Scala Times Issue #619

    Scala Codebase Security Audit Complete. Scala collections: how to pick the right one. How I found 9 compiler bugs via formal methods + Claude. How Cats Changed the Way I Think About Behavior in Scala. Improving Scala's docs and website.


  3. Scala Times Issue #618

    Our impressions from the Scala Survey 2026. ShipReq OSS announcement. Scala Days 2026: Call for proposals open. The Scala Workshop, Jun 29th, Brussels, Belgium. Scala Days, Oct 12th - 13th, Berlin, Germany.


  4. Scala Times Issue #617

    Scala with Claude Code. Apache Pekko 1.6.0. Lift Framework 4.0.0. Scala Days 2026: Call for proposals open. The Scala Workshop, Jun 29th, Brussels, Belgium.


  5. Scala Times Issue #616

    Incremental Highlighting for Scala. Yes, You Can Debug a Scala 3 Macro. Comparing effect systems in Scala: The Problem and Future. Comparing effect systems in Scala: Cats Effect and ZIO. Comparing effect systems in Scala: Kyo, Gears, and Ox.


  6. Scala Times Issue #615

    Safe Scala: an introduction. Event Sourcing with PureLogic. Homogeneous Tuples in Scala 3. Introduction to Scala 3's Capture Checking and Separation Checking. Golem 1.5 features - Part 5: Scala support.


  7. Scala Times Issue #614

    Fixing a Command Injection Vulnerability in sbt. Scala's Momentum in the AI Era. Scala 3.8.3 is now available!. Apache Pekko 1.5. The Scala Workshop CFP, Jun 29th, Brussels, Belgium.


  8. Scala Times Issue #613

    Porting the Scala 2 optimizer to Scala 3. Scala: Learning Roadmap. Job-focused list of product companies using Scala in production. Protobuf Goes Scala-First. Metaprogramming: teaching the compiler to explain your data.


  9. Scala Times Issue #612

    Generating Direct-Style Scala 3 Applications. ScalaWAW #39 - Scalar warmup!, Mar 25th, Warsaw, Poland. Scalar, Mar 26th - 27th, Warsaw, Poland. The Scala Workshop CFP, Jun 29th, Brussels, Belgium. J On the Beach, Oct 29th - 30th, Malaga, Spain.


  10. Scala Times Issue #611

    Migrating sbt plugins to sbt 2 with sbt2-compat plugin. Tracking Capabilities for Safer Agents. Hardening Scoverage Support in Scala 3. Introducing PureLogic: direct-style, pure domain logic for Scala. Rage Against the (Plurality of) Effect Systems.


  11. Scala Times Issue #610

    How I used AI to modify hundreds of logs messages. Hybrid IO-Driven Promise. The Effect Pattern and Effect Systems in Scala. Fairstream: Fair Backtracking. Scala Standard Library Process.


  12. Scala Times Issue #609

    Practical observability: distributed tracing with otel4s. Forms4s: Rapid (Internal) UI Development. Postmortem of scala/scala3#24994. The Sovereign Tech Fund invests in Scala. Two Months of Vibe-Coding: Scala, Constraints, Trust and Shipping.


  13. Scala Times Issue #608

    ZIO Golem: Bringing Golem to Scala. Practical FP in Scala is now FREE!. Direct-style property based testing. RFC: sbt 2.0 on JDK 17. Business4s H2 2025 Highlights.


  14. Scala Times Issue #607

    Scala 3 slowed us down?. Coroutines, Event Loops - Build Your Own in Scala. Advent of Code 2025 in Scala (Solutions). Make delightful web apps with Scala and Krop!. Apache Pekko 2.0.0-M1.


  15. Scala Times Issue #606

    First class support for compilation profiling. Understanding Capture Checking in Scala. Laminar components inside React. Save your Scala apps from the LazyValpocalypse. To Effect or Not to Effect - a Scala Perspective.


  16. Scala Times Issue #605

    Join us for the Advent of Code 2025. Scala Days 2025: Conference Highlights and Talk Recordings. Metals v1.6.4 - Osmium. Scalar, Mar 26th - 27th, 2026, Warsaw, Poland.


  17. Scala Times Issue #604

    Pekko Core 1.3.0. Scalar 2026: Call for Speakers.


  18. Scala Times Issue #603

    Master ZIO: Functional Effect System. Better explanation of what Business4s is. ClickHouse with PlayFramework, Slick, and Evolutions.


  19. Scala Times Issue #602

    Scala 3 / No Indent. Scala 3 / Match Types. Scala 3 / HOCON Parsing. Scala vs F#. Demystifying Scala 3 Types.


  20. Scala Times Issue #601

    An Omakase-style PlayFramework Template: PlayFast. How to run sbt tasks with custom settings. Alexandru Nedelcu | Effects and concurrency in functional programming. Metals v1.6.3 - Osmium. LLM4s Dev Hour – Sundays @ 9am London Time.


  21. Scala Times Issue #600

    One Script, Many Styles - Exploring Scala’s Ecosystem with scala-cli. A simple tool to make illegal states unrepresentable. Exploring Neotype’s capabilities, pitfalls, and limitations in Scala 3. IntelliJ IDEA x Scala: The Debugger (Part 1). Announcing ZIO Test support in scalamock classic (released in 7.5.0).


  22. Scala Times Issue #599

    An old coding challenge I resolved with Scala. Controlling program flow with capabilities. A new repository for Scala nightlies. Effects and concurrency in functional programming. Meet new release of jsoniter-scala with much faster codec derivation.


  23. Scala Times Issue #598

    Effects as Capabilities. Claude Code, Metals, and NVIM. Integrate JobRunr into Play Framework [Update Sep 2025]. Random Scala Tip #534: Adopt an Error Handling Convention for `Future`. Announcing Scala.js 1.20.1.


  24. Scala Times Issue #597

    Understanding Match Types in Scala 3. Scala's Gamble with Direct Style. Custom Error Types Using Cats Effect and MTL. Dealing with Java builder's pattern. Implementing a JWT-based authorization for zio-http.


  25. Scala Times Issue #596

    The Rebirth of Tagless Final: An Ergonomic Approach in Kyo. Hands on Capture Checking. PRE-SIP: Dedented Multiline String Literals. Match Type simulator. LLM4s Dev Hour – Sundays @ 9am London Time.


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