Engineering Log
Technical deep dives from the Plasmate engine team. Design decisions, implementation notes, and lessons from building a browser engine for agents.
Reaching 82% JS Coverage: MutationObserver in a Headless Engine
How we built a functional MutationObserver inside Plasmate's V8 DOM shim, fixed URL polyfill conflicts, and pushed JS-rendered site coverage from 71% to 82% across 100 real-world sites.
Why SOM Exists: Designing a Semantic Object Model
The DOM was built for rendering. Agents need something different. This is how we designed SOM to compress web pages 10x while preserving what matters for reasoning.