Skip to content
Effect Documentation

This Week in Effect - 2026-05-08

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

A steady week for the v4 beta, with new testing utilities, schema additions, and a handful of targeted bug fixes across HTTP, observability, and RPC — here are the most notable changes that landed in effect-smol.

  • New APIs: Added HttpApiTest module for testing HttpApi handlers without a running server, added Effect.acquireDisposable for integrating with the TC39 Explicit Resource Management proposal (using keyword), and ported Effect.firstSuccessOf from v3.

  • Schema additions: Added Schema.DurationFromString for parsing duration strings, and added Config.literals as a convenience constructor for Schema.Literals.

  • RPC: Added Rpc.custom for defining custom RPC handlers with full control over the request/response lifecycle.

  • HTTP: Fixed empty body decoding in HttpApiBuilder, and fixed OpenAI config fields being incorrectly spread into the request body.

  • Observability & runtime: Fixed OpenTelemetry logger severity mapping, moved the fiber lifetime metric start hook to the correct lifecycle point, and fixed formatJson circular reference handling while removing a duplicated stringifyCircular utility.

  • Schema error messages: Normalized SchemaTransformation decoding error messages for more consistent output.

  • Platform: Allowed null for Kubernetes condition lastTransitionTime to handle optional fields in K8s manifests.

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

 

Here are all the technical changes from the past week.

Effect Cluster

 

Community Events

We’re excited to announce that the first Effect Miami Meetup 🇺🇸 has been scheduled on May 28, organized by Ariel Azoulay, and hosted by The LAB Miami.

A reminder of the upcoming Effect Vienna Meetup #2 on May 27, sponsored by Sentry.

Jan Peer Stöcklmair will be the first speaker at the Vienna meetup 🇦🇹, presenting ​Observability with Effect + Sentry.

Visit our Effect Community Events calendar and subscribe for updates on upcoming Effect events and meetups.

 

Community Highlights

 

 

 

  • Fiberplane has been running Claude Code autonomously on their codebase for months, using Effect traces as part of their guardrails for agentic development. Great read!

 

  • effect-boxes - a TypeScript library providing a flex-style layout system for terminal applications within the Effect ecosystem.

 

  • pi-effect-harness - a Pi extension that enforces Effect v4 best practices during agent-assisted coding sessions.

 

  • @nmnmcc/ability - an authorization library bringing Effect-style programming to permission checking.

 

 

  • s20-wifi-setup - a TypeScript command-line tool for connecting legacy Orvibo WiWo S20 smart sockets to Wi-Fi networks.

 

 

Effect Content Update

  • What is Alchemy? Zero-to-Production Infrastructure in TypeScript & Effect | Office Hours 27
Play

 

  • DrainableWorker
Play

 

  • Vibe Engineering Effect Apps by Michael Arnaldi at the AI Engineer Europe in London.

    Play

 

  • Roasting Julius’ code in T3 Code

    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: