Web Almanac
2020
HTTP Archive’s annual
state of the web report
Part IV:
Content
Distribution
Page Weight
We will peel back the layers of web pages, and see what it is that constitutes a page's weight at the possible detriment of the end user: you, I, us.
18. Page Weight
2 MB
median web page transfer size
Images
got the most requests by content type. Followed by JavaScript and CSS.
is the most popular image format and also the largest by size (median 20 KB)
JPG
Compression
Using HTTP compression makes a website load faster and therefore guarantees a better user experience. But what is the status quo on web pages?
19. Compression
of HTTP responses are delivered with no text-based compression.
60%
Compression methods
for different content types
22.1%
62.7%
15.1%
Brotli
Gzip
no compression
It is surprising that while all those content types would profit from compression, the range of percentages varies widely.
5.7%
85.1%
9.2%
11.6%
32.3%
56.3%
application/javascript
text/javascript
text/html
Caching
We will primarily be discussing caching within web browsers, as opposed to caching at the origin server or in a CDN.
20. Caching
90.4%
of responses across all HTTP(S) requests are considered cacheable.
60.2%
of resources served on the web have a cache TTL that could be considered too short compared to its content age.
Cache as much as you can for as long as you can!
Let's take a look at the most predominant resource hints supported by most browsers and analyze the 2020 trends.
21. Resource Hints
Resource Hints
Popularity of resource
hints adoption
dns-prefetch:
preload:
preconnect:
prefetch:
prerender:
33%
18%
9%
3%
0%
20,931
percent of pages using the new Native Lazy Loading API after its first year.
the most preload hints on
a single page.
4.02%
HTTP/2
This chapter reviews the current state of HTTP/2 and gQUIC deployment. It explores how well some of the newer features of the protocol, such as prioritization and server push, have been adopted.
22. HTTP/2
of requests use HTTP/2.
64%
HTTP/2
13
23
vs.
The median number of connections per page on desktop in 2016 vs. 2020.
Server support
The majority of HTTP/2 sites are served by Nginx, Cloudflare and Apache.