Effect 3.14 has been released! 🚀 A summary of what’s new: ▸ LayerMap module ▸ effect/rpc refactor ▸ Effect.linkSpanCurrent ▸ Dual Runtime apis ▸ Option transpose apis More in the blog post below: effect.website/blog/releases/…
This Week in Effect - 2025-03-28
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 wrapped up the Effect Days conference last week!
- The Effect community on Discord reached 3870+ members!
- Effect 3.14 has been released.
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Effect 3.14 has been released!
Here are all the technical changes from the past two weeks (note that changes included in the 3.14 release will not be listed).
- Fix issue with generic filters when generating arbitraries (Bug Fix)
- Add support for jsonSchema annotations on SymbolFromSelf index signatures (Feature)
- Preserve specific annotations when using Schema.typeSchema (Bug Fix)
- Remove Context.ValidTagsById usage (Bug Fix)
- Arbitrary: fix bug where annotations were ignored (Bug Fix)
- Schema: standardSchemaV1 now includes the schema (Bug Fix)
- Fixed typo in jsdocs (Documentation Update)
- Enhance documentation for dual function (Documentation Update)
- Chore: remove unused expression from Either tests (Bug Fix)
- Feat: add Record.findFirst (Feature, next-minor)
- Update ai Generated schemas (Improvement)
- Update version of gpt-tokenizer used by @effect/ai-openai to latest (Optimization)
- Update README.md (Documentation Update)
- Remove Sharding.make export (Bug Fix)
- Add Sharding.activeEntityCount (Feature)
- Re-run codegen (Bug Fix)
- Fix clientOnly mode for SocketRunner (Bug Fix)
- Update ai Generated schemas (Improvement)
- HttpApiEndpoint: add missing head and options constructors (Bug Fix)
- Url improvements (Feature)
- Ensure upgrade socket is closed on http response finish (Bug Fix)
- Ensure rpc does not flatten Effect sub-types (Bug Fix)
- Docs: fix layer referenced in RpcSerialization jsdocs (Documentation Update)
- Fix tsconfig.test.json (Bug Fix)
From March 19-21, we gathered at Palazzo Pancaldi in Livorno for Effect Days 2025, our annual community event, to bring the community together, showcase real-world use cases of Effect in production, and unveil the latest developments for the coming year. Here’s a recap of the highlights for each day:
The event kicked off with a full day of hands-on workshops, the morning session led by Maxwell Brown and the afternoon by Tim Smart.
Kicking off with the morning session with our workshop at Effect Days! 🚀
The second session of the Effect Days workshop is now underway 🚀
Thursday was the main conference day, with talks covering real-world use cases from companies like MasterClass, Zendesk, Vercel, Inato, Expand AI, and DXOS, alongside key updates from the Effect team on upcoming features and the roadmap for the year ahead, including Effect 4.0.
Effective pragmatism By Attila Vecerek @attilavecerek
Rebuilding Redis for great Effect By Ethan Niser @ethanniser
Effect for Domains at @vercel By Dillon Mulroy @dillon_mulroy
Large Language Model Systems with Effect By Elliot Dauber from @markprompt
How we turn the internet into a database with Effect By Tim Suchanek @TimSuchanek from Expand AI
Building Cortex, MasterClass' AI voice chat orchestrator By David Golightly from @masterclass
How DXOS uses Effect to transform AI By Dmytro Maretskyi from @dxo
Closing remarks by Michael Arnaldi, the creator of Effect
The final day focused on community, collaboration, and shared exploration. We hosted a quiet-yet-intense chess simul that added a thoughtful (and fun) twist to the day and revealed that we have some seriously strong chess players in the community! The atmosphere throughout reflected the core of Effect Days — connection, curiosity, and genuine community.
Community Day at Effect Days is underway 🚀
The chess simul is about to start at Effect Days ♟️
- The growing role of Effect in AI, with real-world examples from companies using it in production.
- The introduction of Effect Cluster, a new package for building distributed systems and durable workflows.
- The unveiling of Effect 4.0, bringing major performance improvements across the ecosystem.
- The increasing adoption of Effect as a stable stack in production across companies and use cases, as highlighted in multiple talks.
- The continued value of Effect Days as a space for learning, networking, and exploring opportunities in the ecosystem.
I'm on my way back home. My biggest fear was that I would get so much inspiration at the Effect Days that I would become completely sidetracked and want to try all the new things I just learned. Effect Days just delivered! It was such an amazing conference. A huge shout-out to
Starting next week, all conference talks, interviews, and workshops from Effect Days will be available on our YouTube Channel and across our social media.
Shout out to all attendees and our conference sponsors, Effectful, Inato, and Evryg, for their support!
We can’t wait to see you all again next year!
Still feeling the energy from Effect Days 2025 🔥 Here are a few snapshots from three unforgettable days of talks, interesting conversations, seaside views, and amazing people! Very grateful to our community! 🤍
- The team at DXOS presented Composer, a collaborative local-first workspace with customizable AI-assisted workflows, powered by Effect. A great example of how teams are building real, complex systems with Effect today.
Meet Composer. A collaborative local-first workspace with customizable AI assisted workflows. Think of it as an IDE for your team where users can install and customize plugins from a growing open source community. 🧵
- Theo - t3․gg released a new video on error handling in TypeScript, featuring Effect as one of the best stacks to properly manage errors.
Play
- Matt Rossman published a new guide on Writing dual APIs with Effect.
Many functions in @EffectTS_ support a dual API for convenience whether used in isolation or in pipelines: - withBehavior(effect, fn) - effect.pipe(withBehavior(fn)) This post explores how to write your own functions with the same ergonomics. mattrossman.com/2025/03/23/wri…
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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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.
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