Issue #821: Ruby 4.1's first preview is here

#821 — October 15, 2026

Together with

Ruby 4.1 Preview 1 Released — Two months out from its final release, we get a 4.1 preview to play with, complete with Module#descendants, Ractor-local GC, YJIT on Windows, and a raft of smaller changes. Worth testing to shake out the effects of things like Symbol#to_s returning frozen strings and all Regexp instances being frozen too.

Yui Naruse

Your Rails App Doesn’t Need a Data Warehouse — Slow Rails reports usually get a warehouse and an ETL job. Now numbers lag and you run two systems. TimescaleDB extends the Postgres your app already uses, so analytics run on live data with plain ActiveRecord. Get $1000 credit to start.

Tiger Data (creators of TimescaleDB) sponsor

📊 ZJIT is Now as Fast as YJIT — Shopify is now running the ZJIT compiler in production, where it matches or edges out YJIT on response time while using about 20% less JIT memory. Early and directional only, but a neat milestone.

Max Bernstein

⚡️ IN BRIEF:

🔒 RubyGems.org now shows security warnings on gem version pages, with known advisories from OSV and malware labels on malicious releases.
There's a proposal to speed up Struct and Data to narrow the performance gap with equivalent hand-written classes.
gem.coop's 2027 Gem Fellowship aims to fund 15 Ruby open source projects. Applications open December 1.
🇧🇷 Tropical on Rails has announced its 2027 dates: March 18-19 in São Paulo.

Living in a Booming Time for Ruby — Responding to DHH's Rails World keynote, Julik argues that the Ruby world is in the midst of a creative boom where the community is using AI to fix things and plug gaps that have sat open for years.

Julik Tarkhanov

🚨 Rails 8.0 Support Ends Nov 7. Upgrades on Autopilot With AI — Our AI agent ships small upgrade PRs that pass your test suite; you stay in control. Starting at $497/mo. Join the beta.

FastRuby.io® | AI-native Upgrades on Autopilot sponsor

📄 Adding Custom Thor Commands to Your Rails App – One line in config/boot.rb enables discovery of commands in lib/commands. Ben Sheldon

📄 Escape LIKE Wildcards with sanitize_sql_like – Otherwise a search for % can match all rows… Andy Croll

📄 Deploying a Roundhouse App with Kamal – Shipping Campfire as a Spinel-compiled binary. Greg Molnar

🛠 Code & Tools

RuboCop 1.92 Makes Agents More Welcome — There's a strong focus on making RuboCop easier for coding agents to drive, with richer JSON output, offense caps, an --explain option and a better MCP server. There's a 'mountain' of autocorrection fixes to help humans too.

Bozhidar Batsov

💡 RuboCop's homepage has also been rebuilt and now features a new playground (pictured above) that runs RuboCop in your browser (thanks to ruby.wasm).

The New Relic Alternative With One Price and Every Feature Included — Errors, N+1s, Sidekiq, logs and host metrics in one gem. Unlimited users, free dev-to-dev support, 30-day trial.

AppSignal sponsor

Hot Cell 1.0: Securing Active Storage in the Age of AI — A way to run risky file processing operations in a container with no network and a read-only filesystem. Your app passes it open file handles over a Unix socket. The upcoming Rails 8.2's Active Storage can switch to using it with a config change.

Mike Dalessio (37signals)

Iodine 0.8: A C-Powered Ruby Server Built for Long-Lived Connections — A big rewrite, with network I/O handled by a C event loop outside the GVL. Supports Rack apps, plus the author's event-driven NeoRack API for streaming without tying up Ruby worker threads.

Boaz Segev

💡 Falcon is another option for handling many concurrent connections that uses fibers and the async gem, and supports HTTP/2.

scrap4rb: Find the Messy Tests in a Ruby Project — A small tool, based on Uncle Bob's SCRAP, that scores Minitest tests for smells like missing assertions, heavy mocking and hidden helper work, then gives one piece of advice per file.

Robert Hopman

RailsPreFlight 0.1 – Reads a Rails app and tells you what stands between it and the Rails version you want.
sqlite3-ruby 2.10 – Ruby's SQLite bindings. Now bundles SQLite 3.54.0 and adds Database#serialize and #deserialize to return or populate a database with a binary string.
Bullet 8.3 – Detects N+1 queries and unused eager loading. Now supports the upcoming Active Record 8.2.
Solid Errors 0.8 – Self-hosted, database-backed error tracker for Rails.
Cucumber 12.0 – The plain-language BDD test tool.

📰 Classifieds

Cut your Ruby CI times in half. WarpBuild runs GitHub Actions twice as fast at half the cost. Get $50 in free credits with code START50.

Keep up to date with key releases in numerous tagged programming language ecosystems with the GitHub Release Tracker.

📢 Elsewhere in the ecosystem

🎮 RedGem is an experimental 3D game engine, with its own editor, where you write the gameplay in Ruby (via mruby). Exports games for Linux, Windows and Android. (GitHub repo)
🔒 Trail of Bits tested whether 25 package managers notice a malicious repository tampering with packages. Bundler passes if your Gemfile.lock has a CHECKSUMS section (the default for new lockfiles since Bundler 4), but plain gem install has nothing to check against.
🤖 If you want something like Claude Code/Codex but independent, open and supporting a wider range of models, OpenCode 2.0 is a great option – you can get started here. Pi is also good if you want something minimal.
Lea Verou shows off a neat way to use icons in web UIs and do all the inserting and tweaking with CSS with no HTML involved.
Ryan Bigg, author of several Rails books and Rails contributor, is stepping away from tech after a wave of job rejections.