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
500+ pay-per-call web tools + skill packs for AI agents — every one tested, priced, and settled on-chain. Paid in USDC over x402 on 8 chains, or free via proof-of-work on the pure-CPU tools. Self-hostable, MCP-native, deterministic. Plus the open x402 index (Find / Route / Leaderboard).