Introduction We have enabled Warp, a significant update to SpiderMonkey, by default in Firefox 83. SpiderMonkey is the JavaScript engine used in the Firefox web browser. With Warp (also called WarpBuilder) we’re making big changes to our JIT (just-in-time) compilers, resulting in improved responsiveness, faster page loads and better memory usage. The new architecture is also more maintainable and
![Warp: Improved JS performance in Firefox 83 – Mozilla Hacks - the Web developer blog](https://cdn-ak-scissors.b.st-hatena.com/image/square/edf25afca2324b6cdf9d4dea375e0edf5180dc93/height=288;version=1;width=512/https%3A%2F%2Fhacks.mozilla.org%2Fwp-content%2Fuploads%2F2020%2F11%2Fwarp-diagram-reduced2-500x383-1.png)