Simon Hearne
Web Performance Consultant
The BBC loses an additional 10% of users for every additional second it takes to load | |
Pinterest improved load time by 40% and saw 15% increase in SEO traffic and 15% increase in conversions | |
Financial Times added a one second delay to every page view and saw a 4.9% drop in the number of articles users read over a 7 day window |
COOK increased conversion rate by 7% after cutting average page load time by 0.85 seconds. Bounce rate fell by 7% and session length increased by 10%. | |
For every 100ms decrease in homepage load speed, Mobify's customer base saw a 1.11% lift in session based conversion | |
GQ cut load time by 80% and saw an 80% increase in traffic. Median time spent on the site also increased by 32% |
*mPulse only
*mPulse only
Time to First Byte (TTFB) | The speed of the delivery stack |
DOM Content Loaded (DCL) | The speed of critical dependencies |
First Paint (FP) | The first time something is rendered |
First Contentful Paint (FCP) | When the user might first see content |
Time To Visually Ready (TTVR) | When key content is rendered |
Page Load Time (PLT) | When the page is complete |
Time To Interactive (TTI) | When the app is first responsive to input |
First Input Delay (FID) | How long it takes to respond to input |
* rate of visitors who visit another page after this one
Source: Akamai mPulse (May 2019)
Source: Akamai mPulse (May 2019)
Timer | Goal Speed |
---|---|
First Input Delay (FID) | 200ms |
Time to First Byte (TTFB) | 500ms |
First Contentful Paint (FCP) | 1,000ms |
DOM Ready | 2,500ms |
Time To Visually Ready (TTVR) | 2,500ms |
Page Load Time (PLT) | 3,000ms |
Time To Interactive (TTI) | 4,000ms |
Based on aggregate data - what are yours?
Source: Akamai mPulse (May 2019)
Source: HTTP Archive (May 2019)
we had a collection of very old scripts and couldnβt track the original requester. We removed those on the premise that, if they were important, people would get back in touchβββno one did.
How we shaved 1.7 seconds off casper.com by self-hosting Optimizely
Manage the Impact of Scripts and Get Protection From Unresponsive Third Parties
Source: Akamai mPulse (May 2019)
Always serve quickly, with minimum risk of stale content
Source: Akamai mPulse (May 2019)
Source: HTTP Archive (May 2019)
<link rel="preload" as="font" type="font/woff2" href="font.woff2">
Swap in the brand font when it downloads
font-display: [swap|fallback|optional]
Source: Akamai mPulse (May 2019)
Source: HTTP Archive (May 2019)
Source: HTTP Archive (May 2019)
Source: Akamai mPulse (May 2019)
Source: HTTP Archive (May 2019)
Source: Akamai mPulse (May 2019)
Source: HTTP Archive (May 2019)
The single biggest improvement
(and easiest to implement technically)
came from deferring all JavaScript,
including our own.
simon@hearne.me
simonhearne.com/presentations/improving-engagement/