Using a profiling tool help developers to get detailed information about the execution of their application and allow them to understand the behavior of it. The Firefox Profiler is a profiler that is built into Firefox. It has tighter integration with Firefox than external profilers. It can provide more information and insight into what the browser is doing. It can also show the memory usage and Firefox internal code execution. During the talk, I will be explaining, how to capture a good profile and how to analyze profile data. I will be sharing Firefox Profiler specific features like memory tooling, single tab/advanced view and how to use them. I will also be sharing the future of Firefox Profiler! Web applications are more popular than ever and users expect more from a web application. Unfortunately, they are using applications more frequently from low powered devices, which strains your application’s performance. Managing application performance can be challenging as modern applications have many dependencies and their complexity can hide the issues. Using profiling tools to look for potential bottlenecks can significantly reduce the number of problems in your application. It helps you to get detailed information about the execution of your application and it allows you to understand the behavior of it. The Firefox Profiler is a profiler that is built into Firefox and is available at https://profiler.firefox.com/. It has tighter integration with Firefox than external profilers. It can provide more information and insight into what the browser is doing. Aside from understanding the execution of a web page, it can also show the memory usage and Firefox internal code execution. The intended audience is all web developers and people who want to contribute to Mozilla by helping us analyze the Firefox performance issues by capturing profiles and filing bugs.