# Introduction Here we will talk about many of the different performance problems that you may encounter in a JavaScript application. We will discuss front-end issues such as large file downloads, slow processing, and finding bugs. On the back-end we will discuss scaling across threads and servers using techniques like clustering and micro-services, writing asynchronous code, and dealing with sessions. Most importantly we will be covering how to use data to identify performance issues that matter allowing you to choose what to ignore, what code to modify, and what just needs more hardware. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://www.jedjs.com/master.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.