Boa

Boa is an open-source, embeddable JavaScript engine written in Rust. The project aims to provide a correct, safe, and performant implementation of the ECMAScript specification, with a strong focus on long-term maintainability and developer ergonomics.

Boa is designed to be used as a library, enabling developers to embed JavaScript into Rust applications, tooling, and experimental runtimes. The project emphasizes clear internal architecture, rigorous testing, and close alignment with the evolving ECMAScript standard.

Development is community-driven and spans multiple areas of language runtime engineering, including parsing, bytecode compilation, virtual machine execution, garbage collection, performance optimization, and specification conformance. Boa is actively developed and used as a platform for exploring modern JavaScript engine design in a memory-safe systems programming language.

In 2026 Boa's work has been used in browsers such as Google Chrome and Node.js to implement Temporal, you can read more about this in boajs.dev/blog/2025/09/24/temporal-release. Boa has also been used as an implementation to help drive standards within TC39 (the standards committee behind JavaScript).