WEB PLATFORM
requestIdleCallback()
You might be familiar with requestAnimationFrame(), which is an API that you can use to request function execution before the browser paints — requestIdleCallback is similar (but entirely different), in that you can run a function when the browser is otherwise not doing anything.
I'd not heard anything about it until this tweet by Paolo Fragomeni.
Cheers Paolo!
EXPERIMENTAL / IDEA
Intent to implement: Content size policy
An interesting idea that could give us the ability to set size restrictions on resources (think: third parties). I'm a huge fan of Content security policies, because they really help you realise how many domains and resources a site requires. There's a few error cases to consider with content size policies, but otherwise I'm on-board. 🚢
WEB PLATFORM
Resource timing transferSize attribute
Up until this update to the Resource timing API, it hasn't been possible to retrieve the transfer size of an asset (that's window.performance.getEntriesByType('resource') if you were wondering), but now, you can!
This is a big deal if you wanted to instrument the sizes of assets in your pages to a metrics server. Great to see these additions finally arriving. The jury is out as to when we'll see it in Safari (we won't
for quite some time) 🙈
View the demo (Works in Chrome Canary & Firefox)
USER EXPERIENCE
How Netflix does A/B Testing
Jessie Chen has written her account of a talk by Anna Blaylock and Navin Iyengar, who are product designers at Netflix. Sounded like a great talk, I think Jessie captured it perfectly 💅
ARTICLE
Less wait, more revenue
Everyone loves a solid ROI stat to justify how important user experience is—Here's one to get you right for the week ahead:
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
FUTURE
Google’s QUIC protocol: moving the web from TCP to UDP
Mattias Geniar has written an extensive introduction to Google's recently drafted IETF proposal: QUIC.
I was able to find a complete implementation of QUIC written in Go, and theres mention of support dropping into the Nginx beta channel soon.
NEW IN CALIBRE
Pushing performance monitoring further with actionable insights
Up until recently Calibre has used Google’s Pagespeed Insights API to give performance recommendations to our customers. The ease of deployment, reliability and cost at scale were big winning factors for us — except for when a site used basic or form based authentication.
Simply put, we had no ability to make recommendations for authenticated sites without developing our own analysis suite.
Now, we're taking a big step ahead by launching Performance Recommendations. 🎉
SPREAD THE WORD
As always, we'd love to see more people reading perf.email, so if you'd like to help—Forward this email to a friend, Tweet, or shout from a rooftop. Any mention goes a long way. 👍
Cheers!
Ben