# Effect 4.0 Ships: Dependency-Free Rewrite with 5x Smaller Bundles and Long-Term Support

Source: [InfoQ](https://www.infoq.com/news/2026/11/effect-4-0-release/?utm_campaign=infoq_content&utm_source=infoq&utm_medium=feed&utm_term=global) · 2026-11-10 · Cloud & DevOps
Page: https://themorning.dev/story/effect-4-0-ships-dependency-free-rewrite-with-5x-smaller-bundles-and-long-term-s-a569f48789e3ea85
Kind: release · Impact: medium

## In 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.

## Versions

- Effect 4.0

## Timeline

- 2026-09-30: Effect 4.0 released

## Coverage

- [Effect 4.0 Ships: Dependency-Free Rewrite with 5x Smaller Bundles and Long-Term Support](https://www.infoq.com/news/2026/11/effect-4-0-release/?utm_campaign=infoq_content&utm_source=infoq&utm_medium=feed&utm_term=global) — InfoQ, 2026-11-10

Tags: effect, typescript, release, runtime, performance, structured-concurrency

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Brief generated by AI (claude-haiku-5-5) from the reporting listed under Coverage. Headlines belong to their publishers. The Morning Dev – https://themorning.dev