# This Week in Effect - #128 > Source: > Published: 2026-07-24 00:00:00+00:00 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 and our guide for installing Effect. Enjoy! **Recent major updates:** [Effect v4 Beta](https://effect.website/blog/releases/effect/40-beta/)Release! 🚀[Effect AI SDK](https://github.com/Effect-TS/effect/releases/tag/%40effect%2Fai%400.27.0)Release.- Durable workflows in TypeScript with - currently in alpha.`@effect/workflow` - 6500+ community members on [Discord](https://discord.gg/effect-ts). ## Technology ### Effect v4 Beta updates The first full week on the canonical `Effect-TS/effect` repository was packed, with a thorough `Cron` hardening pass, fiber runtime fixes, new core APIs, and continued AI and HTTP improvements — here are the most notable changes that landed this week. - **Cron hardening**: Validated`Cron.make` field restrictions, fixed`Cron.prev` month day rollover and weekday wrapping, fixed alias normalization, added day and weekday intersection semantics in the inspection representation, and corrected JSDoc examples and documentation accuracy. - **Fiber runtime fixes**: Fixed fiber self-interruption from inside a running observer, cleaned up more references on fiber exit, and fixed`Fiber.joinAll` observers leaking on interruption. Also fixed cache lookup to only interrupt when all awaiters are gone. - **New core APIs**: Added`Effect.reduce` for folding over a collection of effects, and added discriminants to`Schema.toTaggedUnion` for more precise tagged union encoding. - **Schema improvements**: Simplified the displayed`Type` ,`Encoded` , and`Iso` types of required readonly`Schema.Struct` fields for cleaner hover types in editors, and preserved nested class construction when applying constructor defaults. - **HTTP fixes**: Fixed`HttpRouter` middleware context inference, routed multipart errors to HTTP responses, fixed published pre-response handler types, handled aborted HEAD responses during`NodeHttpServer` disposal, and fixed the OpenAPI generator’s handling of recursive schema forward references. - **AI**: Fixed OpenRouter dynamic tools sending an empty parameters schema, preserved OpenAI Responses cache write token usage, and restricted nightly AI codegen to Effect-TS repositories. - **SQL**: Added`disablePreparedStatements` option to`@effect/sql-mysql2` , and avoided creating a table when it’s not needed. - **CLI**: Removed the doubled “Expected” prefix from`InvalidValue` messages, and preserved chained vitest helpers like`it.describe.each` through the`it` proxy. - **MutableList**: Fixed`filter` empty-state handling to prevent incorrect state after filtering all elements. - **Internals**: Ran a dependency audit, moved pnpm config, and upgraded TSTyche. You can follow the full changelog in the [effect repository](https://github.com/Effect-TS/effect/commits/main). To catch up on more updates, check out [ Effect v4 Beta updates](https://effect.website/blog/tags/effect-v4-beta-recaps/). Other technical changes from the past week. ### Effect Core ## Cause & Effect Podcast | Episode #9 **Foldkit: An Effect-First Frontend Framework** Devin Jameson joined Johannes Schickling on the Cause & Effect podcast to talk about [Foldkit](https://foldkit.dev/), an Effect-first frontend framework he’s been building, inspired by Elm architecture. Devin and Johannes discussed why Foldkit takes a schema-first approach to frontend state, how it differs from React, how commands model side effects, and why this architecture may be especially useful in the age of AI-assisted coding. [Play](https://youtube.com/watch?v=MyKLh5CMpeY) The Cause & Effect podcast, hosted by Johannes Schickling, features stories from software engineers and companies that use Effect in production and is available on [YouTube](https://www.youtube.com/@effect-ts), [X(Twitter)](https://x.com/EffectTS_/status/2079159381988626585), and audio platforms like [Spotify](https://open.spotify.com/episode/0xIquYRLjeHIwu1ZhvbmR9) and [Apple Podcast](https://podcasts.apple.com/us/podcast/foldkit-an-effect-first-frontend-framework-9/id1781879869?i=1000777536363). ## Effect Website We redesigned and rebuilt the Effect website! [Check out the public repo](https://github.com/Effect-TS/website) and feel free to post issues / pull requests there. The docs are still for Effect v3 for now. This new website gives us the foundation to build a much better documentation experience for Effect v4, which we’ll continue developing as we move toward the release. We shipped a brand-new Effect website. Take it for a spin, click everything, and let us know what you think. Bugs, feedback, confusing bits, we want all of it ↓ [effect.website](http://effect.website) ## Community Highlights - WELL WELL WELL LOOK HOW THE TURN TABLES -cit. Dillon Mulroy [Replying to @MichaelArnaldi](https://twitter.com/MichaelArnaldi/status/2078110073297989943)I am enjoying effect more and more these days - Effect 🧡 Cloudflare [Replying to @MichaelArnaldi](https://twitter.com/MichaelArnaldi/status/2079663495344169462)and Cloudflare (deployed another service today using Effect) - It’s funny because it’s true. the funny think about effect is that things that the [@EffectTS_](https://twitter.com/EffectTS_)team considers "unstable" are much more stable than most things that other folks consider "stable" - Building Loops for the Real World, by Kyle Mistele (HumanLayer) at AI Engineer World’s Fair 2026. [Replying to @RhysSullivan](https://twitter.com/RhysSullivan/status/2080442902795481513)talked about it at the conf recently - talk hasn't been published yet but here's my slot in the livestream [youtube.com/live/htM02KMNZ…](https://www.youtube.com/live/htM02KMNZnk?t=24389s)We have a really good internal effect program design skill that borrows a a bit from[effect.solutions](http://effect.solutions),[@kitlangton](https://twitter.com/kitlangton)'s effect skill, **Effect.ts + GraphQL | Using Effect RPC to Serve GraphQL** by Lucas Barake. [Play](https://youtube.com/watch?v=jgfS7s0XN6E) - Experimental project by Sandro Maglione. Testing edge cases for the Machine module in [@EffectTS_](https://twitter.com/EffectTS_)One big plus I am seeing: The module pushes you to properly model your state 🏗️ Fully type safe for your agent, fully explicit for you to read and understand [muster](https://github.com/mrtdurdenthe2/muster)- A keyboard-driven TUI for managing your GitHub issues across repositories, built with Effect. By mrtdurdenthe2. ## Effect Team Content Update - Effect v4 RC Prep, CLI Wizard Mode, HTTP API Patterns, Effect Office Hours 38 🔥 [Play](https://youtube.com/watch?v=jgfS7s0XN6E) - Schema.struct vs Schema.class in V4, Schema.opaque vs Plain Struct schemas [Play](https://youtube.com/watch?v=6mNNOQlvYzI) ## Effect Job Opportunities Looking for a role where you can work with Effect? We now have a dedicated Effect jobs page with open roles from companies using Effect. We’ll keep it updated as new opportunities come in. [Explore Effect job opportunities →](https://www.effect.website/effect-jobs) New this week: **Datapizza** is hiring a Software Engineer in Milan, Italy. *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](https://effect.website/merch) offers a selection of Effect-branded items designed for the community. All orders are processed and fully managed through [Printful](https://www.printful.com/). 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](https://effect.website/merch) ## 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*