If you are reading this book, it is probably because you are interested in web development and, in the last few years, the importance of the performance of web applications (such as APIs) is becoming more and more relevant. Here are some stats to give you an idea:
Amazon reported years ago that for every 100 ms of increase in the loading time, their sales decreased by 1%.
Google found that reducing the size of the page from 100 KB to 80 KB diminished their traffic by 25%.
57% of online consumers will abandon a site after waiting for 3 seconds for a page to load.
80% of the people who abandoned the site will not return. About a 50% of these people will tell others their negative experience.
As you can see, the performance of your app can impact your users and even your revenues. In this section, we will give you some tips to improve the overall performance of your web application.