Performance Newsletter


Issue 1



Navigating performance best practices can feel overwhelming. Performance work often feels like an afterthought, even though it is paramount to a joyful and financially successful user-experiences. is a newsletter dedicated to sharing performance and user-experience best practices, tools and case studies.

So tuck in dear reader, we really hope you enjoy. 

Ben Schwarz
Founder of Calibre



Lara Hogan's excellent ‘Designing for Performance’ book, now available in HTML

The book itself isn't new, but it's now available in HTML format, for free!

Lara donates all proceeds of the sale to charities focused on supporting women and people of colour in tech. That said, here is my plan: all readers should purchase a copy of the book, and share the HTML version with your coworkers… and at the very least send Lara a twitter high five 🙌



Netflix launches

The latest project from the Netflix team aims to give their customers a simple, ad-free, download bandwidth test with an easy to remember domain. it is. It works on all modern browsers.



‘Web performance tooling’ — a talk by Paul Irish & Sam Saccone

This 40-minute talk by Paul and Sam covers new features of Chrome dev tools, including the ability to debug a Node.js process using Chrome's JavaScript function inspector.  

Using this technique Sam was able to diagnose an eslint performance issue. Read his (excellent) pull request with all the info. This isn't available in a Node release yet, but you can follow the progress here. 



Chrome 51 removes support for SPDY in favour of HTTP/2

Three huge points for the latest version of Chrome stable:

  • SPDY has been removed in favour of HTTP/2
  • Cross-origin resources (think: ads, video and social embeds) that are outside of the currently visible viewport are no longer sent to the rendering pipeline. This reduces resources by … doing less work — the Chrome team are claiming that it can reduce power consumption by up to 30%
  • Passive event listeners are now supported — this allows sites to run touch and wheel events without blocking scrolling 🙈


The Washington Post launches a Progressive Web App (AMP)

Unfortunately the app is only available for phone user-agents, that aside, the performance is neigh on un-believable. Server responses are said to be 70ms and user 7-day retention increased by a whopping 63%.

Tools, frameworks and approaches aside: this is an impressive project result, and the stats are just as impressive. Kudos. 



“Science the shit out of it” — JPEG compression edition

This in-depth article by Colt McAnlis is a fascinating look at using a library called Butteraugli to test the ‘Psychovisual Error Threshold’ (an image differential algorithm) to achieve the best JPG compression for a given image. 

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