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This Week in Effect - 140

Cluster delivery in Module of the Week. Effect surpasses 50 million downloads per week. 🚀 Effect Miami scheduled for Nov 9.

Davide Scognamiglio Project Manager Mirela Prifti Community Manager

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:

Technology

New Module of the Week post by Maxwell Brown, focusing on Cluster delivery.

Effect v4 updates.

Another busy week on main, with new modules landing alongside a steady stream of fixes across the platform packages. Here are the most notable changes.

  • Additions: Added a GraphQL client and generator, a streaming tar codec in effect/encoding, Schema.toCodecGoJson, Semantic Versioning types with range support, and custom annotation imports for JSON Schema. Also added Path.resolveWithin for root-contained path resolution, Host helpers (toFullyQualified, toRelative, parseHostsFile), NetAddress.loopbackAddresses, fromInput functions for the net data types, and CliOutput.displayWidth.

  • Cluster & workflow: Added a detached option for discarded workflow executions. Failure-suspended workflows now stay parked until resumed or interrupted, suspended callers wake up when their workflow completes, and losing DurableDeferred.raceAll waits are released once the race settles. On the cluster side, shards are now handed off one at a time on shutdown, lease-based SQL shard lock renewal was restored, and a new annotation lets cluster RPCs be interrupted on termination. Also fixed the shards gauge after shard release.

  • RPC, HTTP & platform: RPC gained an onPingTimeout option, and premature socket ping timeouts and connection defects that failed synchronously started requests were fixed. Added WebSocket handshake headers alongside subprotocols and servername support in client TLS upgrades. Fixed HttpRouter prefixes with path params breaking request.url, absolute HTTP URLs in opaque-origin documents, a UTF-8 BOM breaking JSON in Node HTTP text, NodeStream hangs on premature closure, and several child process edge cases.

  • SQL & persistence: Exposed TCP keepalive settings in sql-pg and fixed released connection pins reaching the next borrower and inferred empty array binding. Fixed connection starvation in PGlite, the MSSQL error listener, the ClickHouse migrator ledger, Redis PersistedQueue data loss on lone-surrogate payloads and fractional Redis fixed-window rate limits. Event log replication, remote SQL journal conflicts and persistence expiry checks for reused reads were also fixed.

  • AI: Fixed OpenAI Responses streams not ending at data: [DONE], web search actions without patterns, service tier and provider-nested error metadata, and reasoning replay alongside tool calls in openai-compat. Invalid and undeclared tool calls are now returned when validation is deferred, Anthropic replies from a fallback model now decode correctly, and the Cloudflare provider can send decision images to Clef.

  • Observability: Fixed several OTLP export issues: histogram overflow buckets, integers outside the int64 range, NaN and Infinity values, and batches dropped when a span has a 64-bit B3 trace id. The active span is now recorded on OpenTelemetry log records, and the DevTools client reconnects after socket failures.

  • Core & Schema fixes: Fixed Duration conversions and Duration.times for very large or non-integer inputs, Effect.cached* under synchronous re-entrancy, Stream.timeout ending while the next chunk is pending, and atom rebuild loops from late dependency reads. Match now keeps the unmatched tail in array prefix patterns and rejects unknown keys in object patterns, Array.match exposes NonEmptyArray for mutable arrays, and Schema.Enum preserves literal member inference. Schema also rejects duplicate tagged union discriminants and merges colliding bounds in JSON Schema export instead of emitting allOf.

You can follow the full changelog in the effect repository.

To catch up on more updates, check out Effect v4 Updates, starting from the recently published Effect v4 RC: September 2026 Updates.

Other technical updates from the past week.

Effect Core

Effect AI

Effect Platform

Effect SQL

Community Events

Visit our Effect Community Events calendar and subscribe for updates on upcoming Effect events.

Community Highlights

  • 📈
  • Huge congrats to Expand AI – built with Effect.
  • Coming soon 👀
  • An EffectTS native ORM
  • 💅
  • CAFE stack ☕️
  • Agreed.
  • Yep! 😎

  • CAFE news - By Joel.

  • namera - EVM smart-account wallets for AI agents. By The Namespace.

  • effect-actions - define an Effect action once and expose it over HTTP, MCP, native Toolkits, and CLIs. By gjermundgaraba.

  • effetch - schema-driven HTTP calls on top of Effect v4’s HttpClient. By monarcode.

  • effect-units - typed quantities and unit conversions for Effect, adapted from Elm’s elm-units. By rjdellecese.

  • effect-platform-chrome - Effect v4 services, RPC, and testing utilities for Chrome Manifest V3 extensions. By yotamishak.

  • effect-assistant - build chat assistants that run tools in the background and message the user back, built on Effect and effect/ai. By dbrxnds.

  • effect-views - a prototype for server-rendered HTML and schema-bound forms, built with Effect and htmx. By jpowersdev.

Effect Adoption Partner

We’re thrilled to announce Ziverge as the first Effect Adoption Partner!

Effect Job Opportunities

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.

New this week: Bitfocus & Warp are hiring Effect engineers.

Explore Effect job opportunities →

Disclaimer: Please note that these job postings are shared for informational purposes, and we encourage applicants to verify details directly with the hiring companies.

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.

John A. De Goes, the creator of ZIO, as well as CEO of Ziverge and 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

Effect Team Content Update

  • Effect Office Hours 50 🔥
Play
  • Cluster, Workflows & Cloudflare Durable Objects
Play
  • Effect Cluster, Part 3 | Module of the Week #5
Play

Effect Merch Store

The Effect Merch Store offers a selection of Effect-branded items designed for the community. All orders are processed and fully managed through Printful.

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

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