Http4s
Http4s is a functional, type-safe, and purely functional HTTP library for Scala, built on top of the Cats and Cats Effect libraries. It provides a composable, immutable, and referentially transparent API for building HTTP servers and clients, leveraging Scala's functional programming features. The library is designed to integrate seamlessly with the broader Scala ecosystem, particularly with functional effect systems like Cats Effect and ZIO.
Developers should learn Http4s when building high-performance, scalable, and type-safe HTTP services in Scala, especially in functional programming contexts where immutability and referential transparency are priorities. It is ideal for microservices, REST APIs, and real-time applications that require robust error handling, streaming capabilities, and integration with functional effect systems. Use cases include financial systems, data processing pipelines, and applications needing strict type safety and composability.