Skip to content
Effect Documentation

This Week in Effect - 2026-04-10

Davide Scognamiglio
Davide Scognamiglio
Project Manager
 Mirela Prifti
Mirela Prifti
Community Manager
 Michael Arnaldi
Michael Arnaldi
BDFL

Hi Effecters!

Welcome back to This Week In Effect (TWIE) - your weekly update of the latest developments in the Effect community and ecosystem.

Effect is a powerful TypeScript library that helps developers build complex, synchronous, and asynchronous programs. One key feature that sets Effect apart is how it leverages structured concurrency to provide features such as async cancellation and safe resource management, making it easier to build robust, scalable, and efficient programs.

To get started, below you’ll find links to our documentation as well as our guide for installing Effect. Enjoy!

Recent major updates:

 

Technology

Effect v4 Beta updates

Here are the main changes that landed in effect-smol:

  • Breaking: ServiceMap renamed to Context: The ServiceMap module has been renamed back to Context, realigning with Effect v3 naming conventions. This is one of the most impactful changes of the week for anyone already building on the v4 beta.

  • IndexedDB expansion: Added streaming and offset support to IDB queries, compound index improvements, encoded types for IDB queries, a .reverse() method to IDB selects, a rebuild API for IDB databases, an improved transaction API, and support for customizing IDB durability. Model.Class can now also be used directly for IndexedDB schemas.

  • Schema additions & fixes: Added StringFromBase64, StringFromBase64Url, StringFromHex, and StringFromUriComponent schemas for decoding encoded strings into UTF-8, improved Schema.encodeKeys typing, fixed several missing ~rebuild.out types, fixed duplicate identifier reference reuse, added a compile-time MissingSelfGeneric error for Class APIs, and fixed @category JSDoc tags.

  • RPC & Entity: Added rpc ConnectionHooks, fixed Entity.keepAlive, and improved defect handling when building Entity handlers.

  • Runtime & type inference: Used NoInfer in Layer constructors to prevent type erasure, fixed cache constructor inference by moving the lookup option, fixed type inference for Effect.retry when the times option is provided, and fixed Stream.toQueue types.

  • CLI & HTTP: Fixed unstable CLI boolean flags, underlined active labels in CLI multi-select prompts, added support for form-urlencoded in the OpenAPI generator’s HTTP client format, and added a docs section on customizing schema error responses in HttpApi.

  • PostgreSQL & internals: Guarded transaction acquire failures in PgClient.fromPool, returned resolvers directly from SqlModel.makeResolvers, added KeyValueStore.layerSql, and made Unify.unify work with the Layer module.

You can follow the full changelog directly in the effect-smol repository.

 

Community Highlights

 

 

  • spana – a TypeScript-native end-to-end testing framework for cross-platform test automation across React Native and web (Android, iOS, and web) from a single test suite. Project by wezter96.

 

  • @catenarycloud/linteffect – Biome Grit rules for declarative Effect TypeScript composition and repository-wide style consistency. Project by Roman Naumenko.

 

  • effect-autoagent – a framework for building, optimizing, and deploying AI agents as Effect services. Project by Marc Suesser.

 

  • effect-claudecode - Write Claude Code plugins with Effect v4. Project by Marc Suesser.

 

Effect Content Update

  • Effect Office Hours 24 🔥
Play

 

  • TypeScript-Go with Effect LSP: Setup guide, features, and performance boost.
Play

 

Cause & Effect Podcast

Don’t forget to listen to our Cause & Effect podcast hosted by Johannes Schickling and available on YouTube, X(Twitter), and audio platforms like Spotify and Apple Podcast.

Adam Rankin, CTO at Warp, joined Johannes Schickling to talk about using Effect to bring structure and composability to a growing TypeScript codebase, enabling a small, fast-moving team to stay productive while shipping reliable payment & payroll systems.

Play

 

Effect Job Opportunities

More and more companies are adopting Effect in their projects. Here’s a list of companies looking for software engineers with Effect experience:

Disclaimer: Please note that these job postings are shared for informational purposes, and we encourage applicants to verify details directly with the hiring companies.

 

Effect Merch Store

The Effect Merch Store offers a selection of Effect-branded items designed for the community. All orders are processed and fully managed through Printful.

 

Closing Notes

That’s all for this week. Thank you for being a vital part of our community. Your feedback is highly valued as we fine-tune this format. Feel free to share your thoughts, and we’ll do our best to tailor it to the needs of our community.

Effect Community Team

Tags: