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Jean Boussier @_byroot
Joined April 2022
  • Tweets 1,368
  • Following 199
  • Followers 4,677
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Jean Boussier@_byroot
23 Oct 2023
After several months of work, we finally enabled Pitchfork reforking on 100% of Shopify's monolith. ~30% reduction in memory usage, ~9% better latency and more! railsatscale.com/2023-10-23-…

Effects of Pitchfork reforking on Shopify’s Monolith

Over the last year, I’ve been working on a new Ruby application server called Pitchfork. In most regards it’s extremely similar to the venerable Unicorn, from which it originates, but with one major...

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This one feels good. No more stupid comments at the top of files. At least in one repo.
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Jean Boussier retweeted
Hiroshi SHIBATA@hsbt
Apr 20
I wrote answer letter: github.com/ruby/rubygems/dis…

Proposal: override DSL in Gemfile for managing version constraints · ruby rubygems · Discussion...

Background In the discussion around #9454, reviewers (including @byroot and @Edouard-chin) pointed out that BUNDLE_IGNORE_RUBY_UPPER_BOUNDS and BUNDLE_IGNORE_RUBYGEMS_UPPER_BOUNDS should be express...

github.com
Jean Boussier@_byroot
Apr 20
I wrote some more as a way to fight jet lag, hopefully it's still readable 😅: byroot.github.io/ruby/bundle…
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I wrote some more as a way to fight jet lag, hopefully it's still readable 😅: byroot.github.io/ruby/bundle…

The Missing Bundler Features

Over the last few months, there has been a lot of talk about making Bundler faster, both by improving it directly, or by reimplementing it in another language, and while it may surprise some, that...

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With the new job, I didn't get much time or energy to blog lately, but I figured I'd use the various downtime while traveling to Ruby Kaigi to write about some of the things I worked on recently: byroot.github.io/ruby/perfor…

Optimizing Ruby Path Methods

Back in November last year, I started a new job at Intercom, and one of the first projects I got to work on was improving the Intercom monolith CI with some of my new colleagues.

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Jean Boussier@_byroot
11 Nov 2025
Happy to share that today I'm starting as senior principal at Intercom!
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Jean Boussier@_byroot
28 Oct 2025
I was recently reminded that not everyone fully understand what the frozen string literal magic comment is about. So I figured it was the occasion for another deep dive. byroot.github.io/ruby/perfor…

Frozen String Literals: Past, Present, Future?

If you are a Rubyist, you’ve likely been writing # frozen_string_literal: true at the top of most of your Ruby source code files, or at the very least, that you’ve seen it in some other projects.

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I tried to explain why I don't believe the recent accusations toward my former teammates, as well as how the Ruby and Rails Infra team at Shopify operates and why it can be trusted. byroot.github.io/opensource/…

Dear Rubyists: Shopify Isn’t Your Enemy

I’ve been meaning to write a post about my perspective on Open Source and corporate entities. I already got the rough outline of it; however, I’m suffering from writer’s block, but more importantly,...

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Jean Boussier retweeted
Robby Russell
@robbyrussell
28 Aug 2025
Honored to be back on stage at #RailsWorld in Amsterdam next week to help guide a conversation with @tenderlove, @_byroot, and @hsbt. Still a few days before I lock in the topics. What questions would you love to hear them answer?
Ruby on Rails
@rails
26 Aug 2025
Members of the Rails Core and Ruby committer teams come together for a special session on the #RailsWorld stage next week. @tenderlove, @_byroot, and @hsbt will chat with host @robbyrussell about the future of DevEx in the Ruby and Rails ecosystem, and how foundational tools like RubyGems, Bundler, RDoc, Debug, and ERB can be improved to make the language and framework more welcoming. rubyonrails.org/world/2025/d…
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Jean Boussier@_byroot
11 Aug 2025
I took some time to delve into my latest work on reducing Ractor contention. This time: Generic Instance Variables byroot.github.io/ruby/perfor…

Unlocking Ractors: generic instance variables

In two previous posts, I explained that one of the big blockers for Ractors’ viability is that while they’re supposed to run fully in parallel, in many cases, they’d perform worse than a single...

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Bio update: s/Senior Staff Engineer on Shopify's Ruby and Rails infrastructure team/ funemployed/ After almost 12 years, today was my last day at the company. 🫡
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Beyond performance work, I deprecated a bunch of APIs in the JSON gem, and added others, so I figured it would be a good occasion to talk about API design: byroot.github.io/ruby/json/2…

What’s wrong with the JSON gem API?

As I mentioned at the start of my Optimizing Ruby’s JSON series of posts, performance isn’t why I candidated to be the new gem’s maintainer.

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Jean Boussier retweeted
Peter Zhu@peterzhu2118
3 Jun 2025
I just published "Implementing Embedded TypedData Objects" about a feature @_byroot and I worked on for Ruby 3.3. A bit late, but better than never. railsatscale.com/2025-06-03-…

Implementing Embedded TypedData Objects

We implemented a new feature to TypedData objects in Ruby, called embedded TypedData objects. TypedData objects are used across a wide variety of Ruby types, such as Time, Enumerator, and Method....

railsatscale.com
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Jean Boussier@_byroot
24 May 2025
I wrote a post to braindump what I'm currently working on: allowing lock-free access to class instance variables from Ractors. byroot.github.io/ruby/perfor…

Unlocking Ractors: class instance variables

In a previous post about ractors, I explained why I think it’s really unlikely you’d ever be able to run an entire application inside a ractor, but that they could still be situationally very useful...

byroot.github.io
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Jean Boussier@_byroot
26 Apr 2025
I did some sort of rubber duck blogging about a patch I'm currently working on: byroot.github.io/ruby/perfor…

Unlocking Ractors: object_id

In a previous post about ractors, I explained why I think it’s really unlikely you’d ever be able to run an entire application inside a ractor, but that they could still be situationally very useful...

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Jean Boussier@_byroot
21 Mar 2025
Some personal thoughts on the usability of MySQL and PostgreSQL protocols: byroot.github.io/performance…

Database Protocols Are Underwhelming

If you’ve been in this trade for a while, you have probably seen dozens of debates on the merits and problems of SQL as a relational database query language. As an ORM maintainer, I have a few gripes...

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Here we go. That one I really needed to get of my chest for the better part of a year, so I feel relieved now. It's really long but hopefully not too hard to follow. byroot.github.io/ruby/perfor…

The Pitchfork Story

A bit more than two years ago, as part of my work in Shopify’s Ruby and Rails Infrastructure team, I released a new Ruby HTTP server called Pitchfork.

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Jean Boussier@_byroot
27 Feb 2025
This is the last subject I wanted to talk about before I can start talking about Pitchfork itself. What I think Ractors are useful for, and why that isn't writing web servers: byroot.github.io/ruby/perfor…

What’s The Deal With Ractors?

I want to write a post about Pitchfork, explaining where it comes from, why it is like it is, and how I see its future. But before I can get to that, I think I need to share my mental model on a few...

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Jean Boussier@_byroot
24 Feb 2025
Continuing my series to give context on Pitchfork design, why I think HTTP2 support isn't important (for a Ruby application server). byroot.github.io/ruby/perfor…

There Isn’t Much Point to HTTP/2 Past The Load Balancer

I want to write a post about Pitchfork, explaining where it comes from, why it is like it is, and how I see its future. But before I can get to that, I think I need to share my mental model on a few...

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Jean Boussier retweeted
えむ。@takkanm
22 Feb 2025
🚀 httpclient gem 2.9.0 is out! 🚀 After 8 years, we're thrilled to release this update thanks to amazing contributors! Huge thanks to @yahonda & @_byroot . 🙏 rubygems.org/gems/httpclient…

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One more entry in my series to give context to Pitchfork design. byroot.github.io/ruby/perfor…

Guardrails Are Not Code Smells

I want to write a post about Pitchfork, explaining where it comes from, why it is like it is, and how I see its future. But before I can get to that, I think I need to share my mental model on a few...

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