Bun, Deno, and many other JavaScript runtimes have been hyped, but do you know why? In this talk, attendees will learn the concepts used to create a new JavaScript runtime. They're going to go through an example of how to make a JavaScript runtime by following what's behind the scenes on the Node.js project using C++. They'll learn the relationship between Chrome's V8 and Libuv and what makes one JavaScript runtime better than others. This talk will cover the following topics: - What's a JavaScript Engine - V8 - Why Node.js uses Libuv - How to create a JS Runtime from scratch