Arrow is a library for typed functional programming in Kotlin that provides a common set of interfaces and abstractions across Kotlin libraries.
Arrow addresses the challenge of writing pure functional programs in Kotlin by supplying popular data types such as Option and Either, functional operators like zipOrAccumulate, and computation blocks that enable developers to build applications and libraries using higher-order abstractions. The library aims to establish a shared vocabulary of functional programming concepts across the Kotlin ecosystem, allowing developers to reason about code using typed, composable patterns rather than imperative approaches.
Developers should adopt Arrow if they are building applications or libraries that benefit from functional programming patterns, typed error handling, or need to work with immutable data structures and functional composition. The project suits teams already committed to functional paradigms in Kotlin or those seeking to introduce such patterns incrementally. The library covers multiple domains including typed errors, coroutines and resource management, resilience patterns, immutable data handling, and functional collections, making it applicable across different problem spaces.
The project maintains active community engagement through multiple channels including social media, Slack communities, and Gitter, with explicit welcoming of contributors at all skill levels and offers of mentorship from maintainers. Development is organized around a separate documentation repository, indicating a structured approach to maintaining learning resources alongside the core library. The project describes itself as an actively growing ecosystem with associated libraries and toolsets, suggesting ongoing expansion of its scope and capabilities.
