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:
- We started publishing the talks from Effect Days 2025!
- The Effect community on Discord reached 4090+ members!
- Effect featured in the Thoughtworks Technology Radar.
Technology
Here are all the technical changes from this week.
Effect Core
- Add symbols documentation to Number module (Documentation Update)
- Fixes a bug where non existing properties were allowed in the make constructor of a Schema.Class (Bug Fix)
- JSONSchema: preserve original key name when using fromKey followed by annotations (Bug Fix)
- JSONSchema: apply encodeOption to each example and retain successful results (Bug Fix)
- Fix JSONSchema.make for Exit schemas (Bug Fix)
- Drop use of performance.timeOrigin in clock (Optimization)
- Add property message: string to ConfigError.And & Or (Feature, next-minor)
- Default never type for MutableHasMap.empty & MutableList.empty (Optimization, next-minor)
Effect Cluster
- Fix module import (Bug Fix)
Effect Opentelemetry
- Include error cause in otel exception.stacktrace (Improvement)
Effect Platform
- Chore: tweak HttpApiEndpoint type test (Optimization)
Effect RPC
- Add option to RpcClient socket protocol to retry transient errors (Feature)
- Allow rpc middleware to wrap execution (Feature)
Effect SQL
- Add configuration options to the PgDrizzle layer (Feature, next-minor)
Effect Vitest
General Chore
Effect Days 2025 Updates
This week, we published Ethan Niser’s Rebuilding Redis for great Effect talk, where he walks through Effectis, a Redis-compatible server built entirely with Effect, showing how Effect’s primitives help tackle a real-world system’s challenges: TCP networking, expiration and persistence, pub/sub, transactions with STM, and more.
Community Highlights
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Mattia Manzati, long-term Effect Cluster contributor and Effect Days speaker, joined the Effectful Technologies team. We are excited to have Mattia onboard and wish him a productive and impactful journey ahead!
Thrilled to share that... I’ve joined @EffectfulTech as a Founding Engineer! Beyond excited to work with some of the brightest & kindest ppl I know! I'll be also working on devtools to improve the @EffectTS_ DX! More info soon! PS: Expect more LSP features incoming :P
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A few weeks ago, the DSOX team launched Composer, a collaborative, local-first workspace with customizable AI-assisted workflows built with Effect. The team is looking for direct user feedback, and you can request access on the DXOS website.
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Michael Arnaldi gave a talk at the CityJS London 2025 on April 25, 2025, about Effect: Production-Grade TypeScript.
Ready for #CityJSLondon ⁉️ If you love 💕 #TypeScript you will love this Effect: Production TypeScript with the creator of this amazing library @MichaelArnaldi Get your ticket now 👇 london.cityjsconf.org
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Dillon Mulroy livestreamed another episode of Building BudgetSync with EffectTS 🚀 and two episodes of his new series Building a tool to sync Splitwise and YNAB with EffectTS 🚀 on his Twitch channel.
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 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!
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.
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
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:
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Expand.ai: Founding Engineer
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Platonic Systems: Remote Effect Engineers
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Inato: Senior Product Engineer
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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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Stealth team looking for an Engineer with experience in Effect. 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.
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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.
Disclaimer: Please note that these job postings are shared for informational purposes, and we encourage applicants to verify details directly with the hiring companies.
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