Building Fast Websites Against All Odds

A presentation at DevDay 2018 in May 2018 in Berlin, Germany by Ryan Townsend

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DevDay, Berlin 2018 Building fast websites against all odds Photo by Emil Vilsek on Unsplash

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Who am I? Ryan Townsend CTO, SHIFT – @ryantownsend

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Performance is pretty important… ‘Why Fast Matters’ by @csswizardry – https://bit.ly/2kiVDAz

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Traffic x Conversion Rate x AOV

!!!

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Performance = Traffic

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“The result of rebuilding our pages for performance led to [...] a 15 percent increase in SEO traffic” – Pinterest Source – https://bit.ly/2ICPv4Z

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“[…] starting in July 2018, page speed will be a ranking factor for mobile searches.” – Google Source – https://bit.ly/2Dt5Plz

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Performance = Conversion

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“For every 100ms decrease in homepage load speed, Mobify's customer base saw a 1.11% lift in session based conversion, amounting to an average annual revenue increase of $376,789” – Mobify Source – https://bit.ly/2s0FDHS

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“Similarly, for every 100ms decrease in checkout page load speed, Mobify's customers saw a 1.55% lift in session based conversion, amounting to an average annual revenue increase of $526,147” – Mobify Source – https://bit.ly/2s0FDHS

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Performance = AOV

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+9.6% pages/session

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+8.7% AOV

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Performance x Performance x Performance = !!!

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But it’s not that easy…

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Selling performance can be tricky

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“Can you implement AMP?”

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• Replica of your site • Restricted HTML: limited AMP elements • Restricted JS: no custom JS allowed • Restricted CSS: inlined, 50kb max • No repaint: fixed element sizing • No desktop: mobile-only • Shown within Google’s branding • Stale-while-revalidate: minimum 15 seconds refresh • Extra QA effort

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It’s gonna get expensive

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“But the carousel!”

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“[…] we now feel ready to take the next step and work to support more instant-loading content not based on AMP technology in areas of Google Search designed for this, like the Top Stories carousel” – AMP Project @ Google Source – https://bit.ly/2JakbtC

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Why don’t we just build fast sites in the first place?

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Smithsonian Institution Neg. 83-14878. “It's easier to ask forgiveness than it is to get permission.” – Grace Hopper

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You don’t need permission to build fast websites

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The Slowest Site in the World

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github.com/ryantownsend/slowest-site-in-the-world

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h t t ps://w w w.we bpage te s t.org/e asy

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Initial Results? • Start render: 6.4s • SpeedIndex: 12717 • Interactive: 4.4s • Bandwidth: 2,594 KB

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Connection 2.

<head> 3. CSS 4. Webfonts 5. JavaScript 6. Images

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Connection

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Yo u ca n’ t c o nt ro l yo u r i n f ra st r u c t u re w it h o u t
permission, but you can check features are enabled: • GZIP / Brotli • OCSP for SSL • HTTP/2 • Connection: keep-alive

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<head>

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Correct Order 1.

<meta> character encoding / viewport 2. <title> 3. Resource hints 4. Inline <script> 5. External stylesheet 6. Inline <style> 7. External <script> 8. Anything else, e.g. other meta tags Source – @csswizardry

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Resource Hints • DNS Prefetch • Preconnect (CDN, 3rd parties) • Prefetch • Preload (CSS @imports, @font-face etc)

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Progressive-enhancement, solid support

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Progressive-enhancement, solid support

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Results?

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Start Render SpeedIndex Interactive Bandwidth (- 1 . 8 s ) (+ 1 8 4 ) (- 0 .1 s ) (no change) Value: $6,782,202 / year Value based on Mobify case study

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CSS

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Remove @import

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Inline (Critical) CSS

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Asynchronous below-the-fold CSS

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Results?

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Start Render SpeedIndex Interactive Bandwidth (- 0 .1 s ) (-348) (- 0 . 2 s ) (no change) Value: $376,789 / year Value based on Mobify case study (ide al condi t ions)

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Start Render SpeedIndex Interactive Bandwidth (- 9 0 .1 s ) (- ∞ ) (- 0 . 2 s ) (no change) Value: $339,486,889 / year Value based on Mobify case study (G o ogle Fon ts offline )

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Start Render SpeedIndex Interactive Bandwidth (- 9 0 .1 s ) (- ∞ ) (- 0 . 2 s ) (no change) Value: $38,754 / hour Value based on Mobify case study (G o ogle Fon ts offline )

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Webfonts

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Self-host

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font-display: swap / optional

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Progressive-enhancement, average support

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WOFF2

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Solid support, WOFF1 for IE9-IE11

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unicode-range (bundling f or we b f on ts)

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/* latin */ @font-face { font-family: 'Montserrat'; font-style: normal; font-weight: 400; src: local('Montserrat Regular'), local(‘Montserrat-Regular'), url(/fonts/montserrat.woff2) format('woff2'); unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;

font-display: swap;

}

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Results?

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Start Render SpeedIndex Interactive Bandwidth (- 1 . 8 s ) (-2 5 8 ) (- 0 .1 s ) (no change) Value: $6,782,202 / year Value based on Mobify case study

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JavaScript

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Sync vs Async vs Defer s t ill v aluable ! to be avoide d!

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Don’t let third parties control your performance or uptime

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https://cdnjs.cloudflare.com/ajax/ libs/jquery/3.3.1/jquery.min.js (to be avoide d!)

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Source – https://bit.ly/2ij5XIt

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Bundling & Tree-shaking

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Results?

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Start Render SpeedIndex Interactive Bandwidth (- 0 .1 s ) (- 6 9 1 ) (-2 . 2 s ) (-5KB) Value: $376,789 / year Value based on Mobify case study

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Images

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Foreground vs Background

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<img src=“image.jpg” /> background-image: url(image.jpg) vs

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Hero loaded after lower-priority product images

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Corrected by using a foreground <img>

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Lazy-load Beneath the Fold

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Source – medium.com Lo w-Quali t y Image Pre v ie w (LQ IP)

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Source – medium.com Lo w-Quali t y Image Pre v ie w (LQ IP)

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Serve Appropriate Sizes

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Latest version of all the major browsers

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Serve Appropriate Formats

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Blink-based browsers only "

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Safari only "

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IE/Edge only "

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<picture> <!--[if IE 9]><video style=&#34;display: none;><![endif]--> 
	<source

srcset='hero@1600w.jxr 1600w, ...'

type='image/vnd.ms-photo' /> <source srcset='hero@1600w.jp2 1600w, ...'

type='image/jp2' /> <source srcset='hero@1600w.webp 1600w, ...'

type='image/webp' />

<!--[if IE 9]></video><![endif]--> 
	<img

srcset=' hero@1600w.jpg 1600w, hero@1400w.jpg 1400w, hero@1200w.jpg 1200w, ...'

src='hero@400w.jpg'

			alt=&#39;Hero	Image&#39;	
	/>
</picture> our dif fe re n t f or mats our dif fe re n t size s f allb ack to JPEG w i t h an old-sch o ol <img> ‘src’

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Results?

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Start Render SpeedIndex Interactive Bandwidth (- 1 . 7 s ) (- 6 9 4 8 ) (- 0 .1 s ) (-2,224KB) Value: $6,405,413 / year Value based on Mobify case study

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https://images.guide/

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Show me the money…

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Start Render SpeedIndex Interactive Bandwidth (- 3 . 8 s ) (- 8 4 8 6 ) (-2 .1 s ) (-2,229KB) Value: $14,317,982 / year Value based on Mobify case study

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Original Optimised https://bit.ly/2IViWzf

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What about Dev Day 2018?

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Start Render SpeedIndex Interactive Bandwidth (- 1 . 7 s ) (-2335) (- 5 . 2 s ) (-3,105KB) Value: $6,405,413 / year Value based on Mobify case study

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323,000 tickets

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https://bit.ly/2L6LW3T

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Low-hanging fruit can have immense impact on performance

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Bonus Point!

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Service Workers

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Latest version of all the major browsers

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• Progressive enhancement • Network control • Offline support • Progressive Web Apps (PWAs) • stale-while-revalidate / stale-while-error • Protect against 3rd party slow-downs

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function timeout(delay){ return new Promise(function(resolve, reject) { setTimeout(function(){ resolve(new Response('', { status: 408, statusText: 'Request timed out.' })); }, delay); }); } self.addEventListener('fetch', function(event { event.respondWith(Promise.race([ fetch(event.request), timeout(2000) ])); }); at temp t t he reque s t f orce a 2-se cond t ime ou t

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Thank you! Ryan Townsend CTO, SHIFT – @ryantownsend