Topcoat enables Rust to render server-side web apps

Topcoat is a new framework that enables Rust programming language to create server-side web applications. Rust is not typically used for web development but with AI's assistance, it could be a viable option, according to Carl Lerche, an Amazon Web Services principal engineer. Lerche showcased Topcoat at ScyllaDB’s 2026 P99 virtual conference, highlighting its runtime performance and safety guarantees.

Topcoat compiles Rust code into JavaScript, making it more compatible with web browsers. Unlike other Rust frameworks, Topcoat compiles Rust code into JavaScript, allowing for better interaction with the browser's Document Object Model (DOM). The framework steers clear of reactive programming where program logic is transferred to the browser upon session initiation. Instead, most of the logic executes on the server, with only the results delivered to the browser, similar to server-side rendering.

Server-side rendering is not a new concept and predates reactive programming, but Topcoat modernizes it using better technology. Lerche stated that server-side rendering offers a more efficient and faster user experience, especially for repetitive tasks. Furthermore, Topcoat includes Toasty, a Rust-based asynchronous database object-relational mapper, which allows components to communicate directly with the database, thus streamlining the data loading process.

Although Topcoat is not suitable for complex applications, it can be used for common, database-driven applications that make up 90% of the web today. Compared to other JavaScript frameworks, Topcoat does not provide the full Rust syntax, but it offers a simpler alternative for smaller web projects. Overall, Topcoat aims to bridge the gap between Rust and web development, offering a promising solution for server-side web app creation.