Effect-TS

Effect-TS is the next-generation TypeScript framework: a unified, type-safe functional effect system for robust error handling, concurrency, and dependency management.

This is the core functional effect system for TypeScript development, designed for production-grade robustness. The central `Effect<A, E, R>` type explicitly models a program's success ($ ext{A}$), typed errors ($ ext{E}$), and required dependencies ($ ext{R}$), offering a superior, type-safe alternative to the standard `Promise`. Its 'cold' (lazy) execution model ensures superior composability and enables powerful, built-in features: automatic retries, interruption, and first-class OpenTelemetry tracing and metrics. The extensive ecosystem provides a cohesive set of libraries for everything from HTTP to SQL, ensuring your application logic remains simple, testable (via type-safe dependency injection), and scales with maximum confidence.

https://effect.website/