Top 23 Scala Java Projects

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1. Apache Spark

   1 137 44,093 10.0 Scala

   Apache Spark - A unified analytics engine for large-scale data processing

   

   Project mention: MLOps Lifecycle: Stages, Workflow, and Best Practices | dev.to | 2026-06-02

   Feature transformations should be deterministic: The same input should produce the same output when the same feature definition and configuration are applied. This is what allows training, backtesting, and live inference to remain aligned. Tools such as Pandas, Spark, or feature platforms such as Feast can be used to implement that logic.

2. AppSignal

   www.appsignal.com sponsored

   AppSignal knows why the f*#k it crashed. Stop vibe-debugging. Every exception, every backtrace, grouped so you see patterns, not noise.

   

3. Play

   2 34 12,615 9.8 Scala

   The Community Maintained High Velocity Web Framework For Java and Scala.

   

   Project mention: Weather MCP | dev.to | 2026-03-31

   During my career break that I started in 2025, I started exploring the ever-changing Generative AI landscape. In Decemember, I was exploring Spring Boot as I hadn't used it in anger professionally having used other Java frameworks like Jersey, Play and I wanted to build something.

4. Finagle

   3 24 8,867 5.4 Scala

   A fault tolerant, protocol-agnostic RPC system

   

5. Gatling

   4 32 6,957 9.5 Scala

   Modern Load Testing as Code

   

   Project mention: JMeter vs Gatling: Comparison for Modern Performance Testing | dev.to | 2026-03-22

   And in that world, Gatling has a clear edge.

6. joern

   5 1 3,540 9.7 Scala

   Open-source code analysis platform for C/C++/Java/Binary/Javascript/Python/Kotlin based on code property graphs. Discord https://discord.gg/vv4MH284Hc

   

7. Mill

   6 17 2,795 9.7 Scala

   A better build tool for Java, Scala and Kotlin: Simpler than Maven, easier than Gradle, with 3-7x faster dev workflows than other JVM build tools

   

8. Lagom

   7 0 2,629 5.7 Scala

   Reactive Microservices for the JVM

   

9. SaaSHub

   www.saashub.com sponsored

   SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

   

10. Kamon

    8 1 1,427 2.3 Scala

    Distributed Tracing, Metrics and Context Propagation for applications running on the JVM

    

11. Reactive-kafka

    9 0 1,421 6.7 Scala

    Alpakka Kafka connector - Alpakka is a Reactive Enterprise Integration library for Java and Scala, based on Reactive Streams and Akka.

    

12. adam

    10 3 1,061 0.0 Scala

    ADAM is a genomics analysis platform with specialized file formats built using Apache Avro, Apache Spark, and Apache Parquet. Apache 2 licensed.

    

13. bloop

    11 6 943 9.4 Scala

    Bloop is a build server and CLI tool to compile, test and run Scala fast from any editor or build tool. (by scalacenter)

    

14. Scrooge

    12 0 793 4.6 Scala

    A Thrift parser/generator

    

15. java-webauthn-server

    13 4 564 8.7 Scala

    Server-side Web Authentication library for Java https://www.w3.org/TR/webauthn/#rp-operations

    

16. build-server-protocol

    14 7 547 4.1 Scala

    Protocol for IDEs and build tools to communicate about compile, run, test, debug and more.

    

    Project mention: Escape IntelliJ: Scala and Kotlin LSPs on Emacs Eglot | news.ycombinator.com | 2026-07-23

    Java LSPs are essentially the same approach, headless Eclipse JDT or NetBeans.

    Metals for Scala was an overhaul from the former Eclipse plugin (and Ensime) plus early experiments embedded in the Scala 3 compiler. And Metals v2 is yet another rewrite. It's architectured in a completely different way, see the BSP: https://build-server-protocol.github.io

17. guardrail

    15 2 541 7.5 Scala

    Principled code generation from OpenAPI specifications

    

18. AkkaGRPC

    16 0 432 7.7 Scala

    A platform to build and run apps that are elastic, agile, and resilient. SDK, libraries, and hosted environments.

    

19. kmq

    17 1 342 0.6 Scala

    Kafka-based message queue

    

20. SwayDB

    18 0 298 3.0 Scala

    Persistent and in-memory key-value storage engine for JVM that scales on a single machine.

    

21. spark-extension

    19 1 241 7.0 Scala

    A library that provides useful extensions to Apache Spark and PySpark.

    

22. Play WS

    20 2 224 8.7 Scala

    Standalone Play WS, an async HTTP client with fluent API

    

23. kukulcan

    21 1 116 0.0 Scala

    A REPL for Apache Kafka

    

24. tscfg

    22 1 109 6.2 Scala

    Schema-first, boilerplate-free, type-safe access to configuration properties in Java and Scala

    

25. clojure-news-feed

    23 4 83 6.2 Scala

    evaluating various technologies by implementing a news feed micro-service

    

26. SaaSHub

    www.saashub.com sponsored

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

    

Scala Java related posts

• Zig – New SPIR-V Back End Progress

  5 projects | news.ycombinator.com | 29 Jun 2026

• JMeter vs Gatling: Comparison for Modern Performance Testing

  2 projects | dev.to | 22 Mar 2026

• Add Support for PyCapsule to Pyspark

  1 project | news.ycombinator.com | 28 Jan 2026

• Show HN: Spark – Zero-config IoT deployment tool written in Rust

  2 projects | news.ycombinator.com | 8 Jan 2026

• From Pandas to Upstream Control: The Evolution PyData Needs Next

  1 project | dev.to | 11 Nov 2025

• The Application of Java Programming In Data Analysis and Artificial Intelligence

  1 project | dev.to | 10 Mar 2025

• Apache Spark: Revolutionizing Big Data with Sustainable Open Source Funding

  1 project | dev.to | 6 Mar 2025
• A note from our sponsor - SaaSHub
  www.saashub.com | 7 Oct 2026

  SaaSHub helps you find the best software and product alternatives Learn more →

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