This article is the final piece of a three part series investigating the performance of data URIs on mobile. You can check out my previous posts 'On Mobile, Data URIs are 6x Slower than Source Linking' and 'Data URI Performance: Don’t Blame it on Base64' for more information on the subject.
About a month ago, I did some research to understand why I was seeing poor performance using data URIs in a web component I was building. After posting my results, the most persistent question from the wider web performance community was:
"OK, but how do data URIs perform compared to CSS spriting as a technique to reduce the number of HTTP requests on a page?"
To provide an answer to this question, I’ve conducted further research on data URIs. In this article I’ll provide more background on why the performance of data URIs is an important issue, some additional details about the experiment and, of course, the results of whether data URIs or CSS sprites perform better on mobile.