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Effect Documentation

This Week in Effect - 2026-04-17

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:

  • Schema refinements: Renamed ~rebuild.out to Rebuild for cleaner ergonomics, added Schema.annotateEncoded for annotating the encoded side of a schema, added withDecodingDefaultTypeKey / withDecodingDefaultType, and allowed Class constructors to accept void when all fields are optional.

  • RPC improvements: Added support for deferred responses in RPC, added RpcGroup.omit, and added a require option to AtomRpc.query to make atoms serializable.

  • IndexedDB persistence: Merged the IDB persistence layer, building on the IndexedDB module introduced last week.

  • HttpApi & HTTP: Added support for common string literals in HttpApiSchema.status, and omitted scope from HttpApi handlers to simplify usage.

  • EventLog: EventLog identity now string-encodes to base64.

  • CLI: Fixed an issue with exported CLI completion types.

  • Internals: Fixed SIGINT listener not being removed until fiber exit, updated dependencies, and cleaned up AGENTS.md.

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

 

Community Highlights

 

 

 

 

 

 

  • kbroom-nvim – A Neovim configuration showcasing Effect-inspired patterns for Lua Language Server setup and IDE support.

 

  • effect-encore – A TypeScript library for building Encore.ts applications with Effect.

 

 

  • effect-prodigi – Type-safe TypeScript bindings for the Prodigi print-on-demand REST API, built with Effect. Project by Marc Suesser.

 

  • Effect for TypeScript Developers – A 33-step learning guide introducing TypeScript developers to Effect, covering type-safe error handling, dependency injection, and composable program design.

 

Effect Content Update

  • Effect Office Hours 25 🔥
Play

 

  • Intro to Software Transactional Memory (STM).
Play

 

  • Roasting Tim Smart’s OpenCode PR: refactor effect runtime
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

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