--- title: "How Stripe formatted 25M lines of Ruby" publication: "Ruby Weekly" issue: 799 published_at: "2026-05-07" canonical_url: "https://rubyweekly.com/issues/799" --- Plus a deeper look into Spinel, a Ruby concurrency explainer, and Shopify's 329 billion requests with Falcon. #​799 — May 7, 2026 [Read on the Web](https://rubyweekly.com/issues/799) Together with [![Testdouble\](https://res.cloudinary.com/cpress/image/upload/c_fill,g_auto,w_1280,h_279/e_make_transparent/co_white,e_outline:32/fuxab1jg21v6anerbqwg.png)](https://link.testdouble.com/f65bfc) Ruby Weekly [![\](https://res.cloudinary.com/cpress/image/upload/w_1280,e_sharpen:60,q_auto/dxal0rtiylpxduic5ex2.jpg)](https://paolino.me/ruby-concurrency-what-actually-happens/) [Ruby Concurrency: What Actually Happens](https://paolino.me/ruby-concurrency-what-actually-happens/) — A from-the-ground-up tour of processes, Ractors, threads, and fibers. Concurrency is a common source of confusion, but this guide helps clear up when to reach for which primitive, complete with benchmarks, sequence diagrams, and traces of what happens behind the scenes. Carmine Paolino [![\](https://res.cloudinary.com/cpress/image/upload/c_limit,w_480,h_480,q_auto/copm/352851d0.jpg)](https://link.testdouble.com/f65bfc) [AI Uncertainty and Pressure Causing Existential Dread?](https://link.testdouble.com/f65bfc) — It’s real, and you’re not alone. C-suites pushing AI mandates without strategy. Teams with varying levels of fluency. AI workflows aren’t productive. Test Double offers confidential pairing sessions with experienced humans. Safe space. No judgment. Test Double sponsor [How Stripe Formatted a 25 Million Line Codebase Overnight](https://stripe.dev/blog/formatting-an-entire-25-million-line-codebase-overnight-the-rubyfmt-story) — Stripe boasts _‘the world’s largest Ruby codebase’_ (42 million lines in 2026), so how it reformatted all its code in a weekend using [`rubyfmt`](https://github.com/fables-tales/rubyfmt) is quite the tale. This was before `rubyfmt` migrated to Prism, so it's even faster now. Tales and Mason (Stripe) **⚡️ IN BRIEF:** - ❄️ [Frozen string literals are to be enabled by default](https://github.com/rails/rails/pull/57252) in new Rails apps. It's not the default in Ruby itself, despite years of discussion, but its time is coming. - C extension authors may be interested in [a proposal to add zero-copy `String` constructors](https://bugs.ruby-lang.org/issues/22056) that wrap memory owned by another Ruby object. - Aaron 'tenderlove' Patterson [reflects on the pains caused by AI's use in security reports.](https://tenderlovemaking.com/2026/05/06/rails-security-ai-and-ibb/) - 🇩🇪 Sadly, this year's [_BalticRuby_ event has been cancelled.](https://balticruby.org/) [An Overview of _Spinel_, Matz's AOT Ruby Compiler](https://rubyinside.com/spinel/) — Spinel intrigued me enough last week to dig deeper. Here’s a roundup of how it works, where it came from, what it can and can’t do, and where it could eventually fit into the broader ecosystem. Since last week it’s [gained FFI](https://github.com/matz/spinel/blob/master/docs/FFI.md) support, and someone’s even [written a CRuby extension](https://github.com/kazuho/regexpinel) with it! Peter Cooper [Hanami and Friends Join Forces as _Hanakai_](https://hanakai.org/blog/2026/05/01/welcome-to-hanakai) — The [Hanami](https://hanakai.org/hanami) framework, [Dry](https://github.com/dry-rb), and ROM have all come together under one group to form _Hanakai_, a single group that will grow that garden of aligned gems together. Tim Riley [Surviving Black Friday: 329 Billion Requests with Falcon](https://speakerdeck.com/ioquatix/surviving-black-friday-329-billion-requests-with-falcon) — A RubyKaigi slide deck from the creator of [Falcon](https://socketry.github.io/falcon/), a high-performance, multi-process, multi-fiber HTTP server built for Ruby apps. Shopify is now using it to scale its 15-year-old Rails codebase to incredible levels of traffic. Samuel Williams [Onboarding Legacy Rails Apps Faster with AI](https://sinaptia.dev/posts/accelerating-legacy-systems-onboarding-with-ai?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=rubyweekly-2026q2&utm_content=sponsored) — How SINAPTIA uses AI to understand legacy systems faster and start delivering value sooner. [Let's talk](https://sinaptia.dev/contact-us?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=rubyweekly-2026q2&utm_content=sponsored). SINAPTIA sponsor 📄 [Asset Pipelines: Just Say No](https://blog.julik.nl/2026/05/just-say-no-to-asset-pipelines) – _“I will not be using any frontend bundling nor JS runtime at all. Here’s how you can do the same.”_ Julik Tarkhanov 📄 [Avoid `html_safe` With Tag Helpers, `safe_join`, and `sanitize`](https://andycroll.com/ruby/alternatives-to-html-safe-in-rails/) Andy Croll 📄 [Setting Up AppSignal Server Monitoring for a Rails App on Hatchbox](https://blog.appsignal.com/2026/04/30/setting-up-server-monitoring-for-a-rails-app-on-hatchbox.html) Samuel Mullen (AppSignal) 🛠 Code & Tools [![\](https://res.cloudinary.com/cpress/image/upload/w_1280,e_sharpen:60,q_auto/madcggjwqa94xq2p6rw4.jpg)](https://github.com/crmne/ruby_llm/releases/tag/1.15.0) 🤖 [RubyLLM 1.15.0: Now with Image Editing and Cost Tracking](https://github.com/crmne/ruby_llm/releases/tag/1.15.0) — The popular ‘one stop shop’ API for working with AI models and APIs from Ruby makes it easier to edit existing images with `paint`, and there are now first-class ‘cost helpers’ to get running costs from response, chat, and agent objects. Carmine Paolino [Plug Claude or Cursor into Your Rails App's Production Errors](https://www.appsignal.com/?variant=treatment&utm_source=newsletter&utm_medium=paid&utm_campaign=rubyweekly&utm_term=5-7&utm_content=sponsored-link) — AppSignal MCP feeds your AI the error, trace, and deploy. AI drafts the fix. You review and ship. AppSignal sponsor [Kamal-Backup: Scheduled Rails Backups for Kamal Apps](https://paolino.me/kamal-backup/) — A gem and a Docker image that provide scheduled database _and_ Active Storage backups for Rails apps deployed with Kamal. Carmine Paolino [Fuik: A Webhook Engine for Rails](https://railsdesigner.com/introducing-fuik/) — A Rails engine that catches and stores webhooks from any provider, then gives you a clean way to process them. Rails Designer - 🖼️ [RMagick 7.0](https://github.com/rmagick/rmagick) – The long-standing Ruby interface to ImageMagick drops Ruby 3.1 (and older) as well as old ImageMagick versions. - [SQLite3 v2.9.4](https://github.com/sparklemotion/sqlite3-ruby) – Ruby bindings for [SQLite 3.53.1](https://www.sqlite.org/releaselog/3_53_1.html) (notably you can now use `ALTER TABLE` to add/remove `NOT NULL` and `CHECK` constraints.) - [SuperDiff v0.19.0](https://github.com/splitwise/super_diff) – Get a clear view of differences between complex data structures in RSpec. - [minitest-hooks 1.5.4](https://github.com/jeremyevans/minitest-hooks) – `before_all`/`after_all`/`around_all` hooks for Minitest. - [factory_bot 6.6](https://github.com/thoughtbot/factory_bot/releases/tag/v6.6.0) – The library for setting up Ruby objects as test data. - [rubyzip 3.3](https://github.com/rubyzip/rubyzip/releases/tag/v3.3.0) – Read and write ZIP files from Ruby. - [elasticsearch-ruby 9.4](https://github.com/elastic/elasticsearch-ruby/releases/tag/v9.4.0) – Numerous API updates. 📰 Classifieds 💫 [Lessons-learned](https://judoscale.com/blog/autoscaling-insights-what-nearly-a-decade-of-autoscaling-your-apps-has-revealed-to-us?utm_source=ruby-weekly&utm_medium=newsletter&utm_campaign=lessons-learned&utm_content=jon-from-judoscale): Jon from Judoscale shares what they’ve learned from a decade (!) autoscaling thousands of apps. --- 🔬 "Absolutely essential for AI agent-written PRs." [Undercover CI](https://undercover-ci.com) flags untested methods in every pull request. Free for open source. --- 💎 [Elasticsearch-quality Full-Text Search for Postgres](https://github.com/paradedb/rails-paradedb), now with native ActiveRecord support. Curated by [Peter Cooper](https://twitter.com/cooperx86) and [Glenn Goodrich](https://twitter.com/ruprict). Published by [Cooperpress](https://cooperpress.com/). [Change your email](https://rubyweekly.com/edit_subscription/*|UID|*) or [Stop getting this newsletter.](https://rubyweekly.com/leave/*|UID|*) © Cooper Press Ltd · Fairfield Enterprise Centre, Louth, LN11 0LS, United Kingdom Other weekly newsletters we publish include [Postgres Weekly](https://postgresweekly.com/), [React Status](https://react.statuscode.com/), [Frontend Focus](https://frontendfoc.us/), and [JavaScript Weekly](https://javascriptweekly.com/).