Ruby Garbage Collection in Under Two Hours

What this about?

In this ebook, we'll learn all about how Ruby garbage collection works: from discussing Ruby's memory layout to distinct strategies its garbage collector uses. Many of us program in Ruby for years without ever actually deeply understanding how Ruby garbage collection is seamlessly managing memory behind the scenes.... until now! This ebook will pull back the veil on Ruby garbage collection, leading us to actually understand what's happening behind the scenes, and be able to reason deeply about how Ruby's memory is working.

We'll cover the Tri-Color Mark and Sweep algorithm, generational GC, incremental GC, compaction, and the future of Ruby garbage collection.

You'll Learn


Jemma Issroff

Hi! I’m Jemma (she/hers). I’m a backend software engineer, mainly working in Ruby. I also write, podcast and speak about software development.

I currently have the privilege to work on improving Ruby at Shopify’s Ruby and Rails Infrastructure team. I recently wrote a book about garbage collection. I write the Tip of the Week for Ruby Weekly, and am a rotating co-host of The Ruby on Rails Podcast. I’m also a founder and organizer of WNB.rb, a women/non-binary Ruby group.

In the fall of 2021, I studied at the Recurse Center. Before that, I worked as a backend software engineer at Panorama Education on data integrations and infrastructure teams. For my undergraduate education, I studied computer science and education at Brown University. While I was studying, I interned at Google and Knewton.