How we rebuilt the foundations of component instances

Figma describes how they replaced their decade-old Instance Updater with a new generic framework called Materializer to handle component instance resolution at scale.

• •The original Instance Updater was a monolithic system that handled instance resolution, auto layout, and variable evaluation together, causing cascading update bottlenecks in complex files.
• •Materializer is a generic derived-subtree framework that separates 'what to compute' (blueprint defined by feature code) from 'how to keep it up to date' (handled by Materializer itself).
• •Push-based invalidation with automatic dependency tracking was chosen over pull-based, allowing precise control over which nodes need recomputation when source data changes.
• •A shared runtime orchestration layer was introduced to unify layout engines, variable resolvers, and Materializer under a common update order, eliminating hidden feedback loops called 'back-dirties'.