Shipping Temporal: How a Global Rust Ecosystem Built Chrome’s Newest Web API

This year, Chrome 144 shipped Temporal, the most significant evolution of JavaScript dates and times since the language's inception. But, the real breakthrough is what happened behind the scenes: for the first time, a major new Web API in Chromium wasn't built in C++, but in Rust.
This session provides a look at how we integrated temporal_rs into the heart of V8, marking a new chapter for the Rust ecosystem in the browser. We will discuss how we utilized Diplomat to create ergonomic C++ bindings that bridge Rust’s safety with V8’s internal architecture. We’ll also highlight how ICU4X provided high-performance, data-efficient calendrical calculations.
A key achievement of this journey was using a common library to power both the large, established C++ codebase of V8 and the pure-Rust Boa engine. We’ll show how this collaboration between Google, Igalia, the Unicode ICU4X team, the Boa contributors, and the University of Bergen achieved 99% test262 compliance.
Attendees will leave with a practical framework for building Rust-first components that elevate both new and existing platforms alike.