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Jean Boussier
1,368 posts
user avatar
Jean Boussier
@_byroot
Rails core, Ruby committer, Senior Principal Engineer at Intercom. Bsky: byroot.bsky.social Mastodon: @[email protected]
Toulouse
github.com/byroot
Joined April 2022
199
Following
4,677
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  • Pinned
    user avatar
    Jean Boussier
    @_byroot
    Oct 23, 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!
    Effects of Pitchfork reforking on Shopify’s Monolith
    From railsatscale.com
    21K
  • user avatar
    Jean Boussier
    @_byroot
    Jan 12, 2023
    Just finished upgrading Shopify's monolith to Ruby 3.2.0 today. Average latency: -6.6% Median latency: -5.1% p99 latency: -6.7% And that's without YJIT.
    77K
  • user avatar
    Jean Boussier
    @_byroot
    Dec 7, 2023
    As of this morning Shopify's monolith is running Ruby 3.3.0-dev in production. In the process we fixed over 20 bugs that weren't discovered before. I like to say that this app is the true last boss of Ruby testing.
    57K
  • user avatar
    Jean Boussier
    @_byroot
    Dec 25, 2023
    3 hours later, Shopify's monolith is running Ruby 3.3.0 in production! In case anyone needed any more proof of how solid this release is.
    user avatar
    成瀬
    @nalsh
    Dec 25, 2023
    Ruby 3.3 adds a new parser named Prism, uses Lrama as a parser generator, adds a new pure-Ruby JIT compiler named RJIT, and many performance improvements especially YJIT. ruby-lang.org/en/news/2023/1… Merry Christmas, Happy Holidays, and enjoy programming with Ruby 3.3!
    186K
  • user avatar
    Jean Boussier
    @_byroot
    Oct 5, 2022
    I finally released the first (pre)version of pitchfork github.com/Shopify/pitchf… A new Ruby HTTP Server optimized for latency and memory usage 🧵
  • user avatar
    Jean Boussier
    @_byroot
    Aug 8, 2025
    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. 🫡
    20K
  • user avatar
    Jean Boussier
    @_byroot
    Oct 4, 2024
    I often joke how Shopify's monolith is the true last boss of Ruby. I've just spent 3 days tracking down a weird test failure that turned out to be a parser bug. Millions of lines of code were running fine, only one list was impacted. So easy to miss.
    52K
  • user avatar
    Jean Boussier
    @_byroot
    Oct 9, 2025
    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
    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,...
    50K
  • user avatar
    Jean Boussier
    @_byroot
    Nov 11, 2025
    Happy to share that today I'm starting as senior principal at Intercom!
    27K
  • user avatar
    Jean Boussier
    @_byroot
    Apr 19, 2024
    This morning I upgraded Shopify's monolith from Ruby 3.3.0 to 3.4-dev. We measured a ~4% reduction in latency (with YJIT).
    23K
  • user avatar
    Jean Boussier
    @_byroot
    Jul 21, 2022
    I merged a third String#<< optimization. Overall it's now 65% faster for UTF-8. Unfortunately my profiler is no longer showing any more low hanging fruits, so that may be the last one 😞
  • user avatar
    Jean Boussier
    @_byroot
    Nov 6, 2024
    This morning I though I was done optimizing the ruby/json parser, so I was doing some final cleanups before the 2.8.0 release. But nope, I found two more ~10% wins back to back... This will never end...
    Implement a fast path for integer parsing by casperisfine · Pull Request #692 · ruby/json
    From github.com
    10K
  • user avatar
    Jean Boussier
    @_byroot
    Jan 14, 2025
    It is done, I finally concluded the ruby/json optimization series. I hope you enjoyed it:
    byroot.github.io
    Optimizing Ruby’s JSON, Part 7
    In the previous post, we started covering some parser optimizations. There’s just a handful more to cover until we reached what’s the state of the currently released version of ruby/json.
    6.2K
  • user avatar
    Jean Boussier
    @_byroot
    Oct 24, 2024
    I've just released json 2.7.3 with some bug fixes and lots of performance improvements: github.com/ruby/json/rele… This is my first release after being made maintainer two weeks ago.
    15K

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