How Figma rebuilt the foundations of component instances
Summary
Figma rebuilt its component instance system from scratch to handle accumulated features like auto layout and variables—achieving 2x faster variable propagation. This deep refactor shows how foundational systems need periodic overhauls when feature sprawl creates performance cracks.
Key Takeaways
- Original architecture became a bottleneck as features multiplied (auto layout, variables, slots, instant swapping). A complete system redesign was necessary rather than incremental patches.
- Major architectural changes require massive validation: Figma ran millions of simulations comparing old vs. new system to guarantee pixel-perfect file rendering equivalence before shipping.
- Variable value changes now propagate 2x faster through design files post-refactor, demonstrating quantifiable performance wins from foundation rebuilds in design systems.
- Feature coupling in legacy systems creates compounding complexity—when multiple interdependent features (auto layout + variables + slots) evolved separately, the original framework couldn't scale them together.
Related topics
Transcript Excerpt
My name is Isaac. I'm a software engineer at Figma, and I read this article so you don't have to. Wow, that was hard. Okay, I got this. Components are one of the most powerful features in Figma. They allow users to define content in one place and replicate it all over their file and even in other files, but they're also one of the oldest features that we built. The system that powers components and instances was originally well-suited for the problem, but over time we dramatically expanded the kinds of features that we support, like auto layout variables slots instant swapping, etc. And the original system started to show some cracks. As these features evolved, the original system struggled to keep up. So, we went back to the drawing board and devised a new general-purpose framework that c…