Example projects

Here are some projects which use Arrow and follow the design guidelines. The purpose is showcasing these techiques in bigger applications; docs require small examples for comprehension, but sometimes they don't give the full picture that one of these complete applications can.

Real World

Real World is a blogging platform that has been purposedly created to highlights the possibilities of each language and ecosystem. The linked implementation uses:

• Ktor as HTTP framework.
• SQLDelight for database access.
• Kotest for property-based testing.

Functional Quiz

Service to create an answer quizzes, written in a functional style. Apart from Arrow, this project uses:

• http4k as HTTP framework.
• Exposed for database access.

MasterMind

Implementation of the game using functional event sourcing. The accompanying blog post is part of a series that covers both domain modelling and event sourcing.

Weather App

Small weather forecast application built with Compose Multiplatform Desktop.

• Ktor Client to perform HTTP requests.
• Kotest for property-based testing.
  • Turbine to test ViewModels.

GitHub Alerts

This application manages subscriptions to GitHub repository events, and turns them into Slack messages. It is architected as a series of microservices which communicate using Apache Kafka message queues, by means of kotlin-kafka and Avro4k.

The same project is available using two different sets of technologies.

• The Ktor version uses Ktor as HTTP framework.
  • Cohort for health checks,
  • Tegral for generating OpenAPI specs.
  • SQLDelight for database access.
• The Spring version uses the Spring modules for Kotlin.