Plus a pure Ruby font renderer, jemalloc's return, and does Ruby need Scala-like `for` comprehensions?

#​807 — July 2, 2026

Read on the Web

Together with  FastRuby.io

Ruby Weekly

What Active Rubyists at RubyKaigi Are Using in 2026 — RubyGems's maintainer shares data based upon a survey of RubyKaigi 2026 attendees. It's an interesting sample, as RubyKaigi attendees tend to be active shippers, maintainers, and prominent Rubyists. Ruby 4.0 usage is strong, VS Code dominates, and most are using Claude Code and Docker Compose.

Hiroshi Shibata

💡 On the topic of surveys, the 2026 Ruby on Rails Community Survey closes tomorrow, so take it now if you can.

Rails Experts You Like & Trust, Now Embedded in Your Team 🚀 — Since '17, companies have trusted FastRuby.io with their most complex Rails upgrades. Now those same engineers can scale your team fast: shipping features, fixing bugs, accelerating delivery, and integrating AI effectively. Let's talk!

FastRuby.io® | Staff Augmentation sponsor

Hanami 3.0: The Ruby Framework in Full Bloom — The popular modular app framework rolls out some major features, including mailers, i18n, and Minitest support, along with performance gains. The new homepage does a great job of making Hanami's case. If you want a framework that’s super modular and lets you pick and choose what you need, it's a must-see.

Tim Riley

⚡️ IN BRIEF:

Rails, The Sharp Parts: A Polymorphic Type is Not a Foreign Key — Polymorphic associations aren’t real foreign keys, says Brandon, who shows off the sharp edges around their use. “When people ask me about polymorphic relationships my answer is simply: Don’t.”

Brandon Weaver

Five Rules for Taming RSpec's let Overuse Problem — Concrete, code-backed rules for using let effectively, based on advice from RSpec maintainers and years of consulting. There’s also an agent skill you can use to enforce the idea.

Michael Toppa

Find the Slow Query Killing Your Rails App — AppSignal pinpoints N+1 queries and slow SQL in your Rails app, then shows you exactly what to fix.

AppSignal sponsor

📄 An Introduction to Server Sent Events in Ruby – How to push data in real-time over a single request with Rack 3.0. Brooke Kuhlmann

📄 The 'Constant Frozen at Boot' Bug: A Ruby Exercise for an Interview – A real production bug that makes for a good interview question. Evgeny Zhdanov

📄 When Does an Active Record Query Actually Run?“An ActiveRecord::Relation is deferred query intent, not database truth.” Syed Aslam

📄 Getting Started with Claude Code, on macOS, with chruby and RSpec Jonathan Rochkind

🛠 Code & Tools

Skrift: A Pure Ruby TrueType Font Renderer — A port of the C-based libschrift to Ruby that rasterises TrueType/OpenType outlines. The output can then be rendered in the terminal (above) or saved to an image, etc.

Vidar Hokstad

Classifier: Bayesian and LSI Classification Algorithms — Covers Bayesian classification, logistic regression, LSI, KNN and TF-IDF, for when you want to create text classifiers (e.g. spam filtering or similarity checks) without dragging in a huge ML model.

Lucas Carlson

Jidoka: Automation with a Human Touch — Pair coding agents with senior engineers to modernize legacy code and ship faster with built-in quality.

JIDOKA by SINAPTIA sponsor

jemalloc_rb: Reviving the Alternative Malloc for Ruby — Injects jemalloc into CRuby apps for better memory usage. May be useful now that Meta has committed to working on jemalloc again.

Henrique F. Teixeira et al.

Activepad: A Rails 'Scratchpad' for macOS — A paid app you point at a Rails project (local or remote) to get a tidy editor that provides a Rails console-like experience for building and running Ruby snippets.

Cengiz Gürtusgil

  • Rails Semantic Logger 5.0 – Replaces the Rails default logger with Semantic Logger for structured logging.

  • pru 0.3 – 'Pipeable Ruby' tool that can replace grep/sed/awk, etc. and let you use Ruby expressions instead.

  • Crass 1.0.7 – Pure Ruby CSS parser that supports CSS Syntax Level 3 with tolerance for broken input.

  • rspec-openapi 0.30 – Generate OpenAPI schemas from RSpec request specs.

  • wasmtime-rb 46.0 – Ruby WebAssembly runtime powered by Wasmtime.

  • IRuby 0.8.3 – Ruby kernel for Jupyter/IPython Notebook.

📰 Classifieds

🔬 Shipping AI code? Undercover CI catches untested methods in your PRs before you merge. Coverage percentages won't. Free for open source.


🚂 Rails slow? AppSignal finds N+1s & slow queries fast.


Postgres is already your Rails database. TimescaleDB makes it your analytics database too.

📢  Elsewhere in the ecosystem