The average website loads over 1.5MBs of content per page, making over 75 requests. Many popular websites are serving over 5MBs just to load their homepages. And these numbers represent measurements taken AFTER compression is applied. The full weight of many popular websites is pushing 20+ MBs these days. In an era where performance truly matters to the end user experience, web developers need techniques to help curtail this bloat in data down the wire. No matter how well you optimize, there is no better way than to delete things you do not need. How does one determine what is essential to the user experience and what is not? One answer Chris posits is to develop a hyper-lightweight version of your website which will provide critical insights into your specific performance priorities. This is a process that he has leveraged on many projects, in particular at YouTube to reduce the size of the video watch page from 1.5MBs to 100KBs. In this talk, Chris will take real-world web pages and show techniques for dramatically reducing their page weight and for identifying areas to optimize, while outlining the key steps to doing this well.

1. Chris Zacharias
Hyper-Light Websites
CEO, FOUNDER @
chris@imgix.com
@zacman85
FITC Spotlight: Web Performance

2. “If they can build an entire Quake clone1 in LESS than 100KB,
WHY can’t we get YouTube to load in under 1MB?”
1. https://en.wikipedia.org/wiki/.kkrieger
Mike Solomon
Early engineer at YouTube.

3. YouTube Feather
A hyper-light version of YouTube,
back in 2010.
Constraints
• Start the video as fast as possible.
• Maintain >80% of the user experience.
• Use the latest technologies (circa
2010).
• Make as few requests as possible.

4. Results
• 98KB for “everything but the video”.
• 14 total requests from 3 domains.
• First production HTML5 video player.
• Opened up new regions around the
world.
YouTube Feather
A hyper-light version of YouTube,
back in 2010.

5. High latency environments are EVERYWHERE,
even to this day.

7. A hyper-light website is a RECONCEPTION of a
web-based user interface designed for the purposes
of pushing the limits of performance.

9. Buildinga hyper-lightwebsite.

10. The goal is to provide an experience, roughly consistent
with the real thing, that can be delivered to an end user
AS FAST AS POSSIBLE.

11. Steps to build a hyper-light website:
1. Identify the most active page on your website.
2. Build a new version of that page from scratch with a singular focus on optimization.
3. Assemble all of the HTML, CSS and Javascript into a single “hyper-light” HTML page.
4. Serve the hyper-light page behind a CDN with compression and HTTP/2 pipelining.
5. Measure both the original page, uncached, and the hyper-light page.
6. Analyze the results.

12. Things you want to KEEP doing:
• Serve real content, preferably dynamically.
• Responsive layouts (at minimum, common breakpoints).
• Responsive images.
• Sprites, in some cases.
• SVG graphics (optimized responsibly).
• Accessibility.

13. Things you want to STOP doing:
(for the purposes of this exercise)
• Ads and social media trackers.
• CMS integrations.
• Javascript libraries.
• CSS layouts via frameworks.
• Lazy loading content (except images).
• Data URIs, unless absolutely certain.
• Javascript and CSS compilation.
• Custom web fonts.

14. Arealworldexample.

15. Walking through an example

16. Original
Requests 181
Domains 50
Bandwidth
Total Content
Size
8.7 MBs
Total Transfer
Size
5.9 MBs
Non-Image
Content
2.0 MBs
Image Content 3.9 MBs
Billed By CDN 4.9 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —-—> 2 min 47 sec
3G 6.4 sec ——> 53 sec
Hi-Speed 1.5 sec ——-> 16.7 sec

17. Hyper-Light

18. Walking through an example
Original

19. Original Hyper-Light
Requests 181
🥁
Domains 50
Bandwidth
Total Content
Size
8.7 MBs
Total Transfer
Size
5.9 MBs
Non-Images
Content
2.0 MBs
Image Content 3.9 MBs
Billed By CDN 4.9 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —-—> 2 min 47 sec
3G 6.4 sec ——> 53 sec
Hi-Speed 1.5 sec ——-> 16.7 sec

20. Original Hyper-Light
Requests 181 32 -82.3%
Domains 50 2 -96.0%
Bandwidth
Total Content
Size
8.7 MBs
Total Transfer
Size
5.9 MBs
Non-Images
Content
2.0 MBs
Image Content 3.9 MBs
Billed By CDN 4.9 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —-—> 2 min 47 sec
3G 6.4 sec ——> 53 sec
Hi-Speed 1.5 sec ——-> 16.7 sec

21. Original Hyper-Light
Requests 181 32 -82.3%
Domains 50 2 -96.0%
Bandwidth
Total Content
Size
8.7 MBs 1.1 MBs -87.4%
Total Transfer
Size
5.9 MBs 1.0 MBs -83.1%
Non-Images
Content
2.0 MBs 19 KBs -99.1%
Image Content 3.9 MBs 999.4 KBs -74.4%
Billed By CDN 4.9 MBs 1.0 MBs -79.6%
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —-—> 2 min 47 sec
3G 6.4 sec ——> 53 sec
Hi-Speed 1.5 sec ——-> 16.7 sec

22. Original Hyper-Light
Requests 181 32 -82.3%
Domains 50 2 -96.0%
Bandwidth
Total Content
Size
8.7 MBs 1.1 MBs -87.4%
Total Transfer
Size
5.9 MBs 1.0 MBs -83.1%
Non-Images
Content
2.0 MBs 19 KBs -99.1%
Image Content 3.9 MBs 999.4 KBs -74.4%
Billed By CDN 4.9 MBs 1.0 MBs -79.6%
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —-—> 2 min 47 sec 773 msec ——-> 11 sec 15.7x
3G 6.4 sec ——> 53 sec 556 msec ——> 3.7 sec 14.3x
Hi-Speed 1.5 sec ——-> 16.7 sec 435 msec ——> 621 msec 26.9x

23. Some improvements!

25. Original Improved Hyper-Light
Requests 181
🥁
32
Domains 50 2
Bandwidth
Total Content
Size
8.7 MBs 1.1 MBs
Total Transfer
Size
5.9 MBs 1.0 MBs
Non-Images 2.0 MBs 19 KBs
Image Content 3.9 MBs 999.4 KBs
Billed By CDN 4.9 MBs 1.0 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —> 2 min 47 sec 773 msec —-> 11 sec
3G 6.4 sec —> 53 sec 556 msec —> 3.7 sec
Hi-Speed 1.5 sec —-> 16.7 sec 435 msec —> 621 msec

26. Original Improved Hyper-Light
Requests 181 234 32
Domains 50 74 2
Bandwidth
Total Content
Size
8.7 MBs 1.1 MBs
Total Transfer
Size
5.9 MBs 1.0 MBs
Non-Images 2.0 MBs 19 KBs
Image Content 3.9 MBs 999.4 KBs
Billed By CDN 4.9 MBs 1.0 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —> 2 min 47 sec 773 msec —-> 11 sec
3G 6.4 sec —> 53 sec 556 msec —> 3.7 sec
Hi-Speed 1.5 sec —-> 16.7 sec 435 msec —> 621 msec

27. Original Improved Hyper-Light
Requests 181 234 32
Domains 50 74 2
Bandwidth
Total Content
Size
8.7 MBs 6.2 MBs 1.1 MBs
Total Transfer
Size
5.9 MBs 2.8 MBs 1.0 MBs
Non-Images 2.0 MBs 1.9 MBs 19 KBs
Image Content 3.9 MBs 993.5 KBs 999.4 KBs
Billed By CDN 4.9 MBs 1 MBs 1.0 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —> 2 min 47 sec 773 msec —-> 11 sec
3G 6.4 sec —> 53 sec 556 msec —> 3.7 sec
Hi-Speed 1.5 sec —-> 16.7 sec 435 msec —> 621 msec

28. Original Improved Hyper-Light
Requests 181 234 32
Domains 50 74 2
Bandwidth
Total Content
Size
8.7 MBs 6.2 MBs 1.1 MBs
Total Transfer
Size
5.9 MBs 2.8 MBs 1.0 MBs
Non-Images 2.0 MBs 1.9 MBs 19 KBs
Image Content 3.9 MBs 993.5 KBs 999.4 KBs
Billed By CDN 4.9 MBs 1 MBs 1.0 MBs
Response
Times
(First Paint —>
Fully Loaded)
2G 22 sec —> 2 min 47 sec 7.6 sec —-> 1 min 12 sec 773 msec —-> 11 sec
3G 6.4 sec —> 53 sec 2.7 sec —> 19.3 sec 556 msec —> 3.7 sec
Hi-Speed 1.5 sec —-> 16.7 sec 627 msec —> 9.7 sec 435 msec —> 621 msec

29. Techniquesyoushoulduse.

30. Inline as much as possible server-side.
<!DOCTYPE html>
<html>
<head>
<title>Car and Driver</title>
<style type=“text/css”>
{% include “styles.css” %}
</style>
<script type=“application/javascript”>
{% include “main.js” %}
</script>
</head>
<body>
{% include “sprite.svg” %}
<div>Hello World</div>
</body>
</html>

31. <!DOCTYPE html>
<html>
<head>
<title>Car and Driver</title>
<style type=“text/css”>
{% include “styles.css” %}
</style>
<script type=“application/javascript”>
{% include “main.js” %}
</script>
</head>
<body>
{% include “sprite.svg” %}
<div>Hello World</div>
</body>
</html>
Inline as much as possible server-side.

32. Use HTML5 semantic elements.
<!DOCTYPE html>
<html>
<head>
<title>Car and Driver</title>
</head>
<body>
<header>
<nav></nav>
</header>
<section>
<aside>
</aside>
<article>
Hello World!
</article>
</section>
<footer>
</footer>
</body>
</html>

33. <!DOCTYPE html>
<html>
<head>
<title>Car and Driver</title>
</head>
<body>
<header>
<nav></nav>
</header>
<section>
<aside>
</aside>
<article>
Hello World!
</article>
</section>
<footer>
</footer>
</body>
</html>
95%
of users
Use HTML5 semantic elements.

34. Relative layout using root em sizing.
<style type=“text/css”>
html {
font-size: 16px; /* root ems */
}
h1 {
font-size: 2rem; /* 32 px */
}
img.splash {
width: 50rem; /* 800 px */
height: 40rem; /* 600 px */
}
</style>

35. Relative layout using root em sizing.
96%
of users
<style type=“text/css”>
html {
font-size: 16px; /* root ems */
}
h1 {
font-size: 2rem; /* 32 px */
}
img.splash {
width: 50rem; /* 800 px */
height: 40rem; /* 600 px */
}
</style>

36. CSS grids.
1. https://material.io/design/layout/responsive-layout-grid.html
<html>
<head>
<style type=“text/css”>
#body {
display: grid;
grid-template-columns: repeat(3, 1fr);
grid-gap: 20px;
align-items: top;
}
header {
grid-column: 1 / span 3;
}
article {
grid-column: 1 / span 2;
}
</style>
</head>
<body>
<header>Header</header>
<article>Content</article>
<aside>Side</aside>
</body>
</html>
Header
Side
Content

37. CSS grids.
1. https://material.io/design/layout/responsive-layout-grid.html
<html>
<head>
<style type=“text/css”>
#body {
display: grid;
grid-template-columns: repeat(3, 1fr);
grid-gap: 20px;
align-items: top;
}
header {
grid-column: 1 / span 3;
}
article {
grid-column: 1 / span 2;
}
</style>
</head>
<body>
<header>Header</header>
<article>Content</article>
<aside>Side</aside>
</body>
</html>
Header
Side
Content
87%
of users

38. <html>
<head>
<template id=“article-template”>
<article>
<h1>Title</h1>
<p>Description</p>
</article>
</template>
<script type=“text/javascript”>
function addArticle(title, description) {
var template = document.getElementById(“article-template”);
var clone = document.importNode(template.content, true);
/* Make changes to the clone’s DOM. */
document.getElementById(“articles”).appendChild(clone);
}
</script>
</head>
<body>
<section id=“articles”></section>
</body>
</html>
HTML templates.

39. <html>
<head>
<template id=“article-template”>
<article>
<h1>Title</h1>
<p>Description</p>
</article>
</template>
<script type=“text/javascript”>
function addArticle(title, description) {
var template = document.getElementById(“article-template”);
var clone = document.importNode(template.content, true);
/* Make changes to the clone’s DOM. */
document.getElementById(“articles”).appendChild(clone);
}
</script>
</head>
<body>
<section id=“articles”></section>
</body>
</html>
HTML templates.
89%
of users

40. <style type=“text/css”>
#search-form { display: none; }
#search-form:target { display: block; }
</style>
…
<a href=“#search-form”>Show Search</a>
<form id=“search-form”>
<input type=“text” name=“search-query”>
<input type=“submit” value=“Search”>
<a href=“#”>Cancel</a>
</form>
State transitions using the CSS :target selector

41. <style type=“text/css”>
#search-form { display: none; }
#search-form:target { display: block; }
</style>
…
<a href=“#search-form”>Show Search</a>
<form id=“search-form”>
<input type=“text” name=“search-query”>
<input type=“submit” value=“Search”>
<a href=“#”>Cancel</a>
</form>
Fragment identifier changes WILL get added to the browser history.
⚠
State transitions using the CSS :target selector

42. <style type=“text/css”>
#search-form { display: none; }
#search-form:target { display: block; }
</style>
…
<a href=“#search-form”>Show Search</a>
<form id=“search-form”>
<input type=“text” name=“search-query”>
<input type=“submit” value=“Search”>
<a href=“#”>Cancel</a>
</form>
Fragment identifier changes WILL get added to the browser history.
⚠
State transitions using the CSS :target selector
96%
of users

43. Replacing SVG with HTML and CSS.
Original
2 x SVG arrow graphics = ~5KBs
Hyper-light
Angle quotes + border-radius = 1KB
<style type=“text/css”>
.arrow {
background-color: #4D80AB;
border-radius: 50%;
color: white;
font-weight: bold;
height: 1rem;
width: 1rem;
}
…
</style>
…
<a href=“#prev” class=“arrow”>&lasquo;</a>
<span class=“pages”><em>1</em> of <em>5</em></span>
<a href=“#next” class=“arrow”>&rasquo;</a>

44. Replacing SVG with HTML and CSS.
Original
2 x SVG arrow graphics = ~5KBs
Hyper-light
Angle quotes + border-radius = 1KB
<style type=“text/css”>
.arrow {
background-color: #4D80AB;
border-radius: 50%;
color: white;
font-weight: bold;
height: 1rem;
width: 1rem;
}
…
</style>
…
<a href=“#prev” class=“arrow”>&lasquo;</a>
<span class=“pages”><em>1</em> of <em>5</em></span>
<a href=“#next” class=“arrow”>&rasquo;</a>
93%
of users

45. Using an SVG sprite with fragment identifiers.
<svg xmlns="http://www.w3.org/2000/svg" style="display: none">
<symbol id="icon-comments" viewBox="380 0 20 20">
<title>Comments</title>
<path d=“M394.57,4.19H385a1.2,…” style=“fill: #1383b3;” />
</symbol>
…
</svg>
…
<svg><use xlink:href=“#icon-comments” /></svg>
1. https://css-tricks.com/svg-symbol-good-choice-icons/

46. Using an SVG sprite with fragment identifiers.
<svg xmlns="http://www.w3.org/2000/svg" style="display: none">
<symbol id="icon-comments" viewBox="380 0 20 20">
<title>Comments</title>
<path d=“M394.57,4.19H385a1.2,…” style=“fill: #1383b3;” />
</symbol>
…
</svg>
…
<svg><use xlink:href=“#icon-comments” /></svg>
1. https://css-tricks.com/svg-symbol-good-choice-icons/
91%
of users

47. Image-based sprites.
<style type=“text/css”>
.car-image {
background-image: url(/car-sprite.jpg);
background-size: 100%;
height: 60px;
width: 140px;
}
#sports-car.car-image {
background-position: -280px -120px;
}
</style>
<div id=“sports-car” class=“car-image”></div>

48. In most cases, HTTP/2 pipelining is the better approach.
⚠
Image-based sprites.
<style type=“text/css”>
.car-image {
background-image: url(/car-sprite.jpg);
background-size: 100%;
height: 60px;
width: 140px;
}
#sports-car.car-image {
background-position: -280px -120px;
}
</style>
<div id=“sports-car” class=“car-image”></div>

49. In most cases, HTTP/2 pipelining is the better approach.
⚠
Image-based sprites.
<style type=“text/css”>
.car-image {
background-image: url(/car-sprite.jpg);
background-size: 100%;
height: 60px;
width: 140px;
}
#sports-car.car-image {
background-position: -280px -120px;
}
</style>
<div id=“sports-car” class=“car-image”></div>
96%
of users

50. <img src=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress”
srcset=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress 1x,
https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress&dpr=2 2x”
width=“200” alt=“Honda”>
Responsive images using srcset.

51. <img src=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress”
srcset=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress 1x,
https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress&dpr=2 2x”
width=“200” alt=“Honda”>
Responsive images using srcset.

52. <img src=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress”
srcset=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress 1x,
https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress&dpr=2 2x”
width=“200” alt=“Honda”>
Responsive images using srcset.

53. <img src=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress”
srcset=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress 1x,
https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress&dpr=2 2x”
width=“200” alt=“Honda”>
Responsive images using srcset.

54. <img src=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress”
srcset=“https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress 1x,
https://cnd.imgix.net/honda.jpg?w=200&fm=pjpg&auto=format,compress&dpr=2 2x”
width=“200” alt=“Honda”>
Responsive images using srcset.
88%
of users

55. GZIP compression.
# A simple nginx.conf with gzip turned on.
server {
listen 8080;
server_name localhost;
gzip on;
gzip_comp_level 9;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
}

56. GZIP compression.
# A simple nginx.conf with gzip turned on.
server {
listen 8080;
server_name localhost;
gzip on;
gzip_comp_level 9;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
}
Make sure to vary on Accept-Encoding in your caching layers.
⚠

57. 99%
of users
GZIP compression.
# A simple nginx.conf with gzip turned on.
server {
listen 8080;
server_name localhost;
gzip on;
gzip_comp_level 9;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
}
Make sure to vary on Accept-Encoding in your caching layers.
⚠

58. Experiment with Brotli.
tom@servo:/www$ cd /data/repos && git clone https://github.com/google/brotli.git
tom@servo:/www$ sudo ln -s /data/repos/brotli/python/bro.py /usr/local/bin/bro.py
tom@servo:/www$ bro.py -i index.html -o index.html.br

59. Experiment with Brotli.
tom@servo:/www$ cd /data/repos && git clone https://github.com/google/brotli.git
tom@servo:/www$ sudo ln -s /data/repos/brotli/python/bro.py /usr/local/bin/bro.py
tom@servo:/www$ bro.py -i index.html -o index.html.br

60. Experiment with Brotli.
tom@servo:/www$ cd /data/repos && git clone https://github.com/google/brotli.git
tom@servo:/www$ sudo ln -s /data/repos/brotli/python/bro.py /usr/local/bin/bro.py
tom@servo:/www$ bro.py -i index.html -o index.html.br
84%
of users

61. HTTP/2 pipelining.

62. HTTP/2 pipelining.

63. HTTP/2 pipelining.
84%
of users

64. Measuringandactingonthedata.

65. Measuring the results using Sitespeed.
tom@servo:/data$ docker run -v “$(pwd)”:/sitespeed.io
> sitespeedio/sitespeed.io:7.3.6 https://www.caranddriver.com

66. Zeroing in on the biggest wins.
15 images
requests
~600KBs
1 image request
~50KBs

67. Zeroing in on the biggest wins.
15 images
requests
~600KBs
1 image request
~50KBs
An SVG sprite sheet would be even better at ~15KBs.

68. • Repeat the process with
other pages.
• Run a 1% test in the wild.
• Build a performance
budget.
• Run Sitespeed (or
similar) regularly.
{
"browsertime.pageSummary": [{
"metric": "statistics.timings.firstPaint.median",
"max": 1500
}],
"pagexray.pageSummary": [{
"metric": "transferSize",
"max": 1000000
}, {
"metric": "requests",
"max": 45
}
}
1. https://www.sitespeed.io/documentation/sitespeed.io/performance-budget/
Taking the next steps…

69. Source code:
https://github.com/zacman85/hyperlight-websites
Live demo:
http://hlw.chriszacharias.com
Special thanks to Miguel Cardona.
Thankyou!
Chris Zacharias
CEO, FOUNDER @
chris@imgix.com
@zacman85