On the individual application pages, we only need to read one json file but on the homepage every single JSON files was loaded. The Linux kernel is probably caching every JSON file in the memory so that the IO load wasn’t that bad, but parsing the JSON files still needed to be done on each page load. Rendering a page takes more than just downloading one HTML file, the browser needs to load the other assets (images, CSS and javascript files); it needs to parse the HTML and CSS files and compute the layout.