Effect 4.0 Ships: Dependency-Free Rewrite with 5x Smaller Bundles and Long-Term Support
Effect 4.0, a TypeScript framework for typed errors and structured concurrency, was released on 30 September 2026 with a rewritten fiber runtime. The team reports a bundle size drop from 35.6 kB to 7.1 kB and about 6.4x higher throughput, though these figures are not independently verified. It also adds long-term support through September 2029. By Daniel Curtis
Effect 4.0, a TypeScript framework for typed errors and structured concurrency, was released on 30 September 2026 with a rewritten fiber runtime. The team reports a bundle size drop from 35.6 kB to 7.1 kB and about 6.4x higher throughput, though these figures are not independently verified. It also adds long-term support through September 2029. By Daniel Curtis
