Release
Effect 4.0 Ships: Dependency-Free Rewrite with 5x Smaller Bundles and Long-Term Support
InfoQ · By Daniel Curtis ·
The Brief
- Effect 4.0, a TypeScript framework for typed errors and structured concurrency, was released on 30 September 2026.
- The release includes a rewritten fiber runtime and is described as dependency-free.
- The team reports bundle size dropping from 35.6 kB to 7.1 kB and about 6.4x higher throughput.
Why it matters
Teams using Effect get a major version with a rewritten runtime, which may affect bundle size and performance. The performance figures are the team's own claims.
Who’s affected
- Teams using the Effect TypeScript framework
- Effect 4.0
- #effect
- #typescript
- #release
- #runtime
- #performance
- #structured-concurrency
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…