YJIT is a JIT compiler for Ruby that Shopify has developed. In 2022, we enabled YJIT in all storefront requests and observed ~10% speedups. Do you use an app performance monitor like NewRelic or Scout, or check your daily performance graphs? Here’s how you can make sure YJIT is doing what you want when you monitor. Use what you already have We work hard to make YJIT efficient on various workloads