GitBucket — a Git platform powered by Scala with easy installation, high extensibility & github API compatibility.
Finatra — a lightweight framework for building fast, testable, scala applications on top of TwitterServer and Finagle. Finatra provides an easy-to-use API for creating and testing Finagle servers and apps as well as powerful JSON support, modern logging via SLF4J, Finagle client utilities, and more.
Scalatra is a tiny, Sinatra-like web framework for Scala.
Example:
import org.scalatra._
class ScalatraExample extends ScalatraServlet {
get("/") {
<h1>Hello, world!</h1>
}
}algebird — an abstract algebra for Scala. This code is targeted at building aggregation systems (via Scalding or Apache Storm). It was originally developed as part of Scalding’s Matrix API, where Matrices had values which are elements of Monoids, Groups, or Rings. Subsequently, it was clear that the code had broader application within Scalding and on other projects within Twitter.
The Play Framework combines productivity and performance making it easy to build scalable web applications with Java and Scala. Play is developer friendly with a "just hit refresh" workflow and built-in testing support. With Play, applications scale predictably due to a stateless and non-blocking architecture. By being RESTful by default, including assets compilers, JSON & WebSocket support, Play is a perfect fit for modern web & mobile applications.
Ammonite - Ammonite lets you use the Scala language for scripting purposes: in the REPL, as scripts, as a library to use in existing projects, or as a standalone systems shell.
bitcoin-s-core - An implementation of the Bitcoin protocol in Scala.
Apache Spark - a unified analytics engine for large-scale data processing. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Structured Streaming for stream processing.
Lila - Lila (li[chess in sca]la) is a free online chess game server used by Lichess.org as its main backend. Lila is focused on realtime gameplay and ease of use.