This Week in Effect - #69

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 create 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!

• Effect Documentation
• Installing Effect

Recent major updates:

• Effect Days 2025: Simplifying Forms with Effect & Incremental Adoption of Effect
• Build and run durable workflows in TypeScript with @effect/workflow.
• The Effect community on Discord reached 4300+ members!

 

Technology

• Effect’s LSP 0.18 has been released!

  

  Mattia Manzati

  @MattiaManzati

  · Follow

  Version 0.18 of @EffectTS_ 's LSP has just been released! New features: - Warn about duplicated ecosystem packages - Allow to disable a diagnostic only for a specific line Complete changelog at: github.com/Effect-TS/lang…

  10:54 AM · Jun 4, 2025

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• Major update for all users working with distributed systems: Tim Smart has integrated durable workflows into @effect/cluster.

• An important notice for all the @effect/cluster users: a breaking change has been released to add support for shard grouping.

Here are all the technical changes from the past week.

Effect Core

• Remove this type propagation from Effect.fn (Bug Fix)
• Improve Effect.catchTag auto-complete (Improvement)
• Enable flaky Metrics histogram test (Feature)
• Ensure Cause.YieldableError extends Error (Bug Fix)
• Don’t inherit interruption flag in Effect.addFinalizer (Bug Fix)

Effect AI

• Improve @effect/ai llm schema compatibility (Improvement)
• Fix the type of AiToolkit.Any (Bug Fix)

Effect Cluster

• Add @effect/workflow (Feature)
• Ensure Workflow.interrupt triggers compensation (Bug Fix)
• Add ClusterCron module (Feature)
• Add shard groups, to allow entities to target specific runners (Feature)
• Optimize for requests with a WithExit reply (Optimization)
• Ignore runners that cannot be parsed (Bug Fix)
• Add EntityProxy, EntityProxyServer, WorkflowProxy, WorkflowProxyServer (Feature)
• Do not resume already running workflows (Bug Fix)
• Expose Sharding.pollStorage api (Improvement)
• Make registerEntity a no-op on clientOnly cluster (Improvement)

Effect Experimental

• Fix Machine initialize R argument (Bug Fix)

Effect Language Service

• Update LSP to 0.18.0 (Feature)

Effect Platform

• Ensure HttpApi security middleware cache is not shared (Bug Fix)
• Allow wrapping a web Response with HttpServerResponse.raw on some platforms (Feature)
• Allow literals in HttpApiSchema.param (Improvement)
• Expose MessageStorage in cluster clientOnly layers (Improvement)

Effect RPC

• Add @effect/workflow (Feature)
• Fix RpcClient error types when using discard (Bug Fix)

Effect Workflow

• Add @effect/workflow (Feature)
• Add Activity.onError (Feature)
• Add Workflow.withCompensation (Feature)
• Support typed cause for Workflow withCompensation (Feature)
• Add EntityProxy, EntityProxyServer, WorkflowProxy, WorkflowProxyServer (Feature)
• Add Activity.raceAll (Feature)

General Chore

• Chore: upgrade TSTyche

 

Effect Days 2025 Updates

This week, we published the talk by Jérémie Dayan and the workshop by Tim Smart.

Jérémie Dayan introduced @inato-form, a new form framework powered by Effect and Effect Schema.

Play

Tim Smart showed how to adopt Effect incrementally, with a focus on:

• wrapping Promise-based libraries with the use pattern;
• integrating Effect into Express and React apps; and
• tracing, observability, and proper resource handling.

Play

 

Community Highlights

• AI Engineer released a new video, Building Reliable Support Agents Using the Effect Typescript Library, by Michael Fester, where he walks through how his team built production-ready support agents using Effect. Michael is CEO of 14.ai, a Zendesk alternative for AI agents.

  Play

• FrostyTools built Highlight Hunter, a tool that automatically combs Twitch streamers’ VODs for memorable moments, giving them easy stream-summary-montages as well as quick access to get short clips, powered by Effect on the back-end, which made it production-ready.

• Dillon Mulroy livestreamed five episodes of his new series Building a DNS Resolver with EffectTS 🚀 on his Twitch channel.

 

Effect Content Update

• Maxwell Brown was live on X(Twitter) and Twitch on Tuesday with a new episode of Building an Effect-native MCP Server.
  

  Effect | TypeScript for the AI Era

  @EffectTS_

  · Follow

  Building an Effect-native MCP Server x.com/i/broadcasts/1…

  2:01 PM · Jun 2, 2025

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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.

This podcast highlights stories from software engineers and companies using Effect in production. Each episode explores their journey of adopting Effect, including the learning process, challenges faced, and benefits of integrating Effect into their tech stack.

We’ve published our second episode with Michael Fester from Markprompt about scaling AI-powered customer support with Effect, building reliable and high-performance infrastructure, and enhancing developer productivity in a fast-evolving AI landscape. Let us know your thoughts on our social media or Discord!

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:

• Expand.ai: Founding Engineer

• Platonic Systems: Remote Effect Engineers

• Inato: Product Engineers / Fullstack Engineers

• Medbill.ai: Founding Software Engineers (full-stack and backend)

• Oneiro Solutions: Software Engineer - Core Team. Join Effect Discord and DM leighman for further info.

• Microsub: TS Developer

• Samsung Food: Full Stack Developer

• Margins: Product Engineer

• Precurion looking for a remote‑first Founding Engineer with Effect experience. The job posting is available in the #job-board channel on our Discord.

• Vitalize is hiring a full-stack engineer with Effect experience: Senior Full-Stack Engineer

• Embedded Insurance is hiring for a Senior Software Engineering position.

• Betalyra, an AI consulting company from Portugal, is looking for a part-time freelance software engineer (Typescript/Effect) with AI experience. The job posting is available in the #job-board channel on our Discord.

• Software Intelligence Works: Senior Full-Stack Engineer

• Stealth team looking for a software engineer with Effect experience. The job posting is available in the #job-board channel on our Discord.

• A French-speaking startup team led by Stephan Le Dorze is looking for a freelancer to join them - see his LinkedIn post for more details.

• Freckle.io, is hiring Platform Engineers with experience in Effect.

• A stealth team that has already scaled their product to 50K daily active users in the last year, is looking for Effect Developers. DM wireless on X for more info.

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

In December 2024, we unveiled the Effect Merch Store with a selection of Effect-branded items designed for the community. All orders are processed 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