IBM/fp-go

Functional programming library for Go 1.24+, inspired by fp-ts. Uses generic type aliases for a clean, composable API. Provides Option, Either, Result, IO, IOResult, Reader, and ReaderIOResult monads, plus optics (Lens, Prism, Traversal) for immutable data manipulation. Supports Functor, Applicative, and Monad abstractions with do-notation-style

223 best points · 173 comments · 2 Hacker News posts · 2,034 GitHub stars · View on GitHub

Hacker News discussions

• FP-Go: Functional programming library for Golang (223 points, 172 comments, by arpanetus, 2023-08-18)
• FP-Go V2: Enhanced Functional Programming for Go 1.24 (1 points, 1 comments, by mroche, 2026-03-13)