So instead we introduced the loading spinner on each widget. Nothing is actually any faster, but the whole experience feels more responsive

Simply reducing some CSS transition times from 500ms to 250ms, and cutting others out entirely, made the whole dashboard feel snappier and more responsive.

This means content is served from the nearest possible geographic location to the user, cutting down request latency from as high as 2500ms (in places such as Singapore) to tens of milliseconds

We eventually came up with a compromise solution based on Addy Osmani’s basket.js, using a combination of server-side script concatenation and localStorage for caching. In a nutshell, the page includes a lightweight loader script, which figures out which JS and CSS it has already cached and which needs to be fetched. The loader then requests all the resources it needs from the server in one request, and saves all the resources into localStorage under individual keys. This gives us a great compromise between cutting down the number of HTTP requests while still being able to maintain cacheability, and not re-downloading code unnecessarily when it hasn’t changed. Addtionally, after running a few benchmarks, we found that localStorage is (sometimes) actually faster than the native HTTP cache, especially on mobile browsers.