Simon Willison’s Weblog

Using Rust in non-Rust servers to improve performance (via) Deep dive into different strategies for optimizing part of a web server application - in this case written in Node.js, but the same strategies should work for Python as well - by integrating with Rust in different ways.

The example app renders QR codes, initially using the pure JavaScript qrcode package. That ran at 1,464 req/sec, but switching it to calling a tiny Rust CLI wrapper around the qrcode crate using Node.js spawn() increased that to 2,572 req/sec.

This is yet another reminder to me that I need to get over my cgi-bin era bias that says that shelling out to another process during a web request is a bad idea. It turns out modern computers can quite happily spawn and terminate 2,500+ processes a second!

The article optimizes further first through a Rust library compiled to WebAssembly (2,978 req/sec) and then through a Rust function exposed to Node.js as a native library (5,490 req/sec), then finishes with a full Rust rewrite of the server that replaces Node.js entirely, running at 7,212 req/sec.

Full source code to accompany the article is available in the using-rust-in-non-rust-servers repository.