Letterbox

Overview

• Letterbox is built with open source software and third-party libraries
• We are grateful to the open source community for making these tools available
• Below is a summary of the key third-party software used and their respective licenses

Frameworks & Languages

• Scala — Apache License 2.0 — scala-lang.org
• Play Framework — Apache License 2.0 — playframework.com
• http4s — Apache License 2.0 — http4s.org
• Cats — MIT License — typelevel.org/cats
• Cats Effect — Apache License 2.0 — typelevel.org/cats-effect

Libraries

• Circe (JSON) — Apache License 2.0 — circe.github.io
• Doobie (database access) — MIT License — tpolecat.github.io/doobie
• Enumeratum (enumerations) — MIT License — github.com/lloydmeta/enumeratum
• PureConfig (configuration) — Mozilla Public License 2.0 — pureconfig.github.io
• Log4cats (logging) — Apache License 2.0 — typelevel.org/log4cats
• Logback (logging) — EPL 1.0 / LGPL 2.1 — logback.qos.ch
• Flyway (database migrations) — Apache License 2.0 — flywaydb.org
• Fly4s (Flyway wrapper) — Apache License 2.0 — github.com/geirolz/fly4s
• Prometheus Client (metrics) — Apache License 2.0 — prometheus.io
• Google Guice (dependency injection) — Apache License 2.0 — github.com/google/guice

Database

• PostgreSQL JDBC Driver — BSD 2-Clause — jdbc.postgresql.org
• H2 Database — EPL 1.0 / MPL 2.0 — h2database.com

Frontend

• Bootstrap — MIT License — getbootstrap.com
• Twirl (templating) — Apache License 2.0 — github.com/playframework/twirl

Infrastructure

• sbt (build tool) — Apache License 2.0 — scala-sbt.org
• Docker (containerisation) — Apache License 2.0 — docker.com
• Eclipse Temurin (JDK) — GPLv2 + Classpath Exception — adoptium.net

Testing

• MUnit — Apache License 2.0 — scalameta.org/munit
• ScalaTest — Apache License 2.0 — scalatest.org
• Pact4s (contract testing) — Apache License 2.0 — github.com/jbwheatley/pact4s
• Testcontainers — MIT License — testcontainers.com