@EffectTS_ 3.15 has been released! - Effect.catchTag can now handle multiple error types in one pass - Effect.filterOr* apis have better type inference - Stream.toAsyncIterable Plus a bunch of other improvements.
This Week in Effect - 2025-05-16
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!
Recent major updates:
- Effect Cluster by Tim Smart (Effect Days 2025)
- The Effect community on Discord reached 4210+ members!
- Effect featured in the Thoughtworks Technology Radar.
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Effect 3.15 has been released!
Mattia Manzati released two major updates to Effect’s Dev Tools:
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The Effect’s LSP diagnostics are now also available at compile time thanks to ts-patch.
The @EffectTS_ 's LSP diagnostics are now available also at compile time thanks to ts-patch! 1) setup ts-patch 2) add the transform in your tsconfig 3) have fun!
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TS interfaces and type aliases can now be transformed into an Effect Schema with a single refactor click.
Just baked from the oven! Convert your TS interfaces and type aliases into an @EffectTS_ Schema with a single refactor click!
Here are all the technical changes from the past two weeks (note that changes included in the 3.15 release will not be listed).
- Ensure generic refinements work with Effect.filterOr* (Bug Fix)
- Preserve name & this in Effect.fn apis (Bug Fix)
- More type-safeHashMap.has/get (Bug Fix)
- Add Schedule.CurrentIterationMetadata Reference (Feature, next-mior)
- Refactor the AI packages (Refactor)
- Preserve tool call results in AiResponse.merge (Bug Fix)
- Ensure that the finish reason is set properly (Bug Fix)
- Ensure that multiple tool calls are processed properly for OpenAi (Bug Fix)
- Add EntityNotAssignedToRunner error (Improvement)
- Remove content headers for FormData bodies (Bug Fix)
- Add HttpBody.formDataRecord (Feature)
- Add apis for implementing and accessing single rpc handlers (Feature)
- Ensure socket close events are not errors in RpcServer (Bug Fix)
This week, we published Tim Smart’s Effect Cluster talk, where he introduces Effect Cluster, a distributed runtime for Effect, and a major step toward production-grade systems in TypeScript.
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This week, we celebrate another community milestone: Effect reached 9k stars on GitHub🌟
9k 🌟
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Lucas Barake published a new video, Goodbye Fetch, Hello Effect’s HttpClient.
Play -
Kishore is working on an Effect Playground that runs totally on web browser without any server.
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Aleks Marchenko released his first iteration of an Avro codec for effect/Schema.
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A reminder that the 5th edition of the Effect Paris Meetup is coming on May 20th, hosted by Spiko and sponsored by Evryg. The meetup will be in French.
The next @EffectTS_ Paris meetup (#5) I'm co-organizing is happening on May 20th! Once again, this edition will be hosted by @Spiko_finance in their brand-new office, and sponsored by @EvrygDotCom Paris folks, be sure to register for the event! meetup.com/fr-FR/effect-p…
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Dillon Mulroy livestreamed five episodes of his series Building a tool to sync Splitwise and YNAB with EffectTS 🚀 on his Twitch channel.
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Mattia Manzati was live on Twitch and X(Twitter) with a new episode of Building an Effect Warehouse App.
Welcome to our live show! x.com/i/broadcasts/1…
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Maxwell Brown and Tim Smart were live on X(Twitter) and Twitch on Tuesday with a new episode of Reimagining ContentLayer with Effect.
Re-Imagining Contentlayer with Effect x.com/i/broadcasts/1…
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 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. Give it a listen and let us know what you think on our social media or Discord!
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.
Effect Merch is here! We’re excited to announce the launch of our Effect merch page! Grab your favorite swag & show your love for Effect in style! 🧢 effect.website/merch
More and more companies are adopting Effect in their projects. Here’s a list of companies looking for software engineers with Effect experience:
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Expand.ai: Founding Engineer
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Platonic Systems: Remote Effect Engineers
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Medbill.ai: Founding Software Engineers (full-stack and backend)
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Oneiro Solutions: Software Engineer - Core Team. Join Effect Discord and DM leighman for further info.
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Microsub: TS Developer
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Samsung Food: Full Stack Developer
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Precurion looking for a remote‑first Founding Engineer with Effect experience. The job posting is available in the
#job-boardchannel on our Discord. -
Vitalize is hiring a full-stack engineer with Effect experience: Senior Full-Stack Engineer
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Stealth team looking for a software engineer with Effect experience. The job posting is available in the
#job-boardchannel on our Discord. -
Stephan Le Dorze is looking for a French-speaking freelancer to join him in a small team in a startup - see his LinkedIn post for more details.
Disclaimer: Please note that these job postings are shared for informational purposes, and we encourage applicants to verify details directly with the hiring companies.
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