This Week in Effect - 136

Effect, the TypeScript library for building synchronous and asynchronous programs, published its weekly community update, This Week in Effect - 136, detailing continued release-candidate hardening plus new capabilities in sql-pg, HTTP, and Crypto. The update adds support for the QUERY HTTP method, exposes HttpApi.ParseOptions for endpoint-level schema decoding control, decodes timestamp and timestamptz columns as Date in sql-pg, and adds ULID support to the Crypto module. On the AI side, the release fixes OpenAI web search to support API sources and resolves several MCP server issues around tool strictness, server instructions, and prompt titles; the project also launched a Module of the Week blog series run by Maxwell Brown, starting with PersistedQueue.

Hi Effecters Welcome back to This Week in Effect, your weekly update of the latest developments in the Effect community and ecosystem. Effect is the TypeScript library for the AI era, helping 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: We’ve just launched Module of the Week https://effect.website/blog/module-of-the-week , a new blog series run by Maxwell Brown https://x.com/maxwellbrown , to help the community learn about the lesser-known parts of Effect, one module at a time. Read about PersistedQueue https://effect.website/blog/module-of-the-week/persisted-queue , the first module featured in the series. Introducing Module of the Week: a new series exploring the bits of @EffectTS https://twitter.com/EffectTS you wish you'd knew about earlier. effect.website/blog/module-of… https://effect.website/blog/module-of-the-week The RC hardening effort continued this week, alongside several new capabilities in sql-pg , HTTP, and Crypto. - New HTTP method support : Added support for the QUERY HTTP method, and exposed HttpApi.ParseOptions for finer control over schema decoding and encoding at the endpoint level. - sql-pg improvements : Added support for startup parameters and opaque connection options, added decoding of timestamp / timestamptz columns as Date , decoded unregistered scalar OIDs as UTF-8 text, added support for Effect-based password providers, and preserved SqlError when LISTEN connections fail. - Crypto : Added ULID support to the Crypto module. - Cluster & durable execution : Fixed mailbox starvation caused by unrelated workflow deferreds, fixed lost durable deferred wakes in discarded cluster workflows, fixed deferred handover wake-ups and interrupted RPC stream writes, fixed deferred self-completion in the memory workflow engine, and fixed RunnerServer request leaks on caller disconnect. - HTTP fixes : Preserved Content-Type on file responses and in HttpStaticServer , fixed literal action suffixes across HttpApi , and kept raw Web Response bodies readable in toClientResponse . - Durable Objects sqlite-do : Added support for nested storage transactions, and propagated native transaction completion failures correctly. - Data & parsing : Fixed YAML indentless sequence and multiline scalar parsing, added Arbitrary.array with structural shrinking, restricted ByteSize string inputs to canonical integer quantities, and fixed a multipart hang when the request body fails during an active file upload. - AI : Fixed OpenAI web search to support API sources, and fixed several MCP server issues around tool strictness, server instructions, and prompt titles. - Effect & Stream : Aligned Effect and Stream API signatures and fixed several Stream type signature inconsistencies. - Documentation : Updated v3-to-v4 migration guidance for MCP handlers, tool results, and byte sizes. 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 Updates https://www.effect.website/blog?category=effect-v4-updates , starting from the recently published Effect v4 RC: August 2026 Updates https://www.effect.website/blog/effect-v4-rc-august-recap . Other technical updates from the past week. - Still thinking about Effect Days https://effect.website/effect-days ? 2-day passes are available, but going fast The conference is scheduled for December 9–11, 2026, in Livorno, Italy.I’ll be speaking here about @warpdotco https://twitter.com/warpdotco ’s effect journeyEffect Days is back 🇮🇹 Join us on December 9–11 for three days with the people building Effect and the people building with it. Workshops. Talks. Community. Early Bird tickets are now live ↓ effect.website/effect-days Effect Days is coming up in December I’ll be speaking about Foldkit. Come hang out in Livorno 🇮🇹 effect.website/effect-days https://effect.website/effect-days - NYC and SF, there’s still time to sign up for our meetups this month: Effect NYC https://luma.com/2e0qaazh on Sep 24 and Effect San Francisco https://luma.com/all-things-effect on Sep 30.The Effect community is meeting on both US coasts this September: 🗽 NYC - Sep 24, 6:30 PM luma.com/2e0qaazh https://luma.com/2e0qaazh 🌉 SF - Sep 30, 5:30 PM luma.com/all-things-eff… https://luma.com/all-things-effect Come spend an evening talking all things Effect - Thank you to all our Effecters attending Effect Warsaw https://luma.com/29fn6spj this week, as well as Kris, Daniel, and Monika for organising Effect is coming to Poland 🇵🇱 We are hosting @EffectTS https://twitter.com/EffectTS meetup in Warsaw in September It's going to be beginner friendly, pinky promise Get your ticket at: luma.com/29fn6spj https://luma.com/29fn6spj - Effect Office Hours 🔥 every Wednesday at 10:00 AM ET / 16:00 CET on our YouTube channel https://www.youtube.com/@effect-ts . Visit our Effect Community Events calendar https://luma.com/effect-community and subscribe for updates on upcoming Effect events. We’re thrilled to announce Ziverge as the first Effect Adoption Partner Here are 3 things we're thrilled to announce, as part of our partnership with @EffectfulTech https://twitter.com/EffectfulTech , creators of @EffectTS https://twitter.com/EffectTS 🔥 ➡️ Ziverge will be sponsoring Effect Days ➡️ We have produced an Effect SDK for @GolemCloud https://twitter.com/GolemCloud ➡️ We've launched an @EffectTS https://twitter.com/EffectTS Training Workshop Sign up for - Cloudflare + Effect + Alchemy 🚀 Cloudflare + Alchemy @alchemy run https://twitter.com/alchemy run + Effect @EffectTS https://twitter.com/EffectTS is such a winning stack with AI agents, it's not even real. Provides pretty much all the primitives you need for building any kind of application and ensures proper guardrails & rules to keep the agent on track. And all - Tim strikes again Coming in an upcoming @EffectTS https://twitter.com/EffectTS release - 🪄 the subtle bugs that tend to slip into prod undetected is why i’m an @EffectTS https://twitter.com/EffectTS convert. Best stack investment of 2026. - proof https://github.com/Fawwaz-2009/proof - a Bun-monorepo starter template on the Effect v4, Cloudflare, and Alchemy backbone where every pull request deploys its own isolated preview and merging ships to production. By Fawaz Alharbi. - effect-virtual-fs https://github.com/lloydrichards/effect-virtual-fs - Effect-native virtual filesystem packages, including an in-memory FileSystem implementation, for running Effect programs against isolated, reproducible filesystem state without touching the host disk. By Lloyd Richards. - effect-viz v3.0.0 release https://github.com/topheman/effect-viz/releases/tag/v3.0.0 - the Effect runtime visualizer adds slow motion playback, a stepper to pause and walk through scheduling decisions one at a time, mid-run speed changes, keyboard shortcuts, and an offline fallback mode. By Christophe Rosset. - Triplex https://github.com/bjacobso/triplex - an Effect-native fact database. By Ben Jacobson. - Typed https://github.com/TylorS/typed - Build reactive applications, accessible interfaces, and your own libraries. by Tylor S. Don’t forget to listen to our Cause & Effect podcast hosted by Johannes Schickling and available on YouTube https://www.youtube.com/@effect-ts , X Twitter https://x.com/EffectTS /status/2085682364315783506 , and audio platforms like Spotify https://open.spotify.com/episode/12L2neeIte6LUYQpzTh9n6 and Apple Podcast https://podcasts.apple.com/us/podcast/software-engineering-in-the-age-of-ai-10/id1781879869?i=1000780438320 . John A. De Goes, the creator of ZIO https://zio.dev/ , as well as CEO of Ziverge https://www.ziverge.com/ and Golem Cloud https://golem.cloud/ , joins Johannes Schickling and Michael Arnaldi to discuss how AI is reshaping software engineering, what developers should still learn, and why Effect’s primitives are especially valuable for coding agents. Play https://youtube.com/watch?v=irmz5X3c7Do - Effect Office Hours 46 🔥 Play https://youtube.com/watch?v=nDLHfRr4ip8 - Drizzle transactions with Effect v4. Play https://youtube.com/watch?v=buVkEFVHETM Looking for a role where you can work with Effect? We now have a dedicated Effect jobs page featuring open roles from companies that use Effect. We’ll keep it updated as new opportunities come in. Explore Effect job opportunities → https://www.effect.website/effect-jobs Disclaimer: Please note that these job postings are shared for informational purposes, and we encourage applicants to verify details directly with the hiring companies. 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 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 Previous Module of the Week - PersistedQueue https://effect.website/blog/module-of-the-week/persisted-queue