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4 May 2021

⚡️ 74: Prioritise assets to boost speed

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Performance Newsletter
[issue 74]()
 
#### Editor’s note
 
In life, a lot of different things compete for our attention. Similarly, many assets compete to be downloaded and parsed by the browser when you request to see a site.
 
Without focus or prioritisation, in both cases, it’s easy to become overwhelmed and stuck. What do I pay attention to? Which one of those things is important right now? You can sense trouble brewing.
 

In web performance, it’s critical to audit, select and implement asset prioritisation. Without clearly signifying what should take priority, we’re introducing easily avoidable but significant delays.

**When everything is important, nothing is.**

 
Karolina
 
 
 
 
#### What’s Performance newsletter?
 

Performance Newsletter is a fortnightly mailing by [Calibre](https://calibreapp.com), featuring web performance tools, talks and resources.

Don’t worry—we don’t spam. If you’d like to leave, [unsubscribe]() at any time. Suggest content [here](mailto:[email protected]).

 
 
 
# Articles  
 
The Critical Request: How to Prioritise Requests to Improve Speed
 
### [The Critical Request: How to Prioritise Requests to Improve Speed](https://calibreapp.com/blog/critical-request)
 
[Ben Schwarz](https://twitter.com/benschwarz)
Controlling the priority of the most critical assets to your site can drastically improve initial load and rendering. Learn how to select and prioritise critical requests.
 
The Humble <img> Element And Core Web Vitals
 
### [The Humble Element And Core Web Vitals](https://www.smashingmagazine.com/2021/04/humble-img-element-core-web-vitals/)
 
[Addy Osmani](https://twitter.com/addyosmani)
Imagery has become an indispensable part of the web. Learn how images impact Core Web Vitals and how to mitigate future speed issues.
 
Web developer's guide to AVIF images
 
### [Web developer’s guide to AVIF images](https://darekkay.com/blog/avif-images/)
 
[Derek Kay](https://twitter.com/darek_kay)
With more and more browsers enabling AVIF support, it’s an excellent time to experiment with its implementation and testing. Know how to develop and debug AVIF imagery.
 
### [More time, tools, and details on the page experience update](https://developers.google.com/search/blog/2021/04/more-details-page-experience?s=09)
 
[Jeffrey Jose](https://twitter.com/jeffjose)
The upcoming change in search ranking signals that introduces Core Web Vitals as ranking factors has been pushed from May to mid-June.
 
 
 
# Case Studies  
 
Speeding Ahead with a Systematic Approach to Web Performance
 
### [Speeding Ahead with a Systematic Approach to Web Performance](https://eng.lyft.com/speeding-ahead-with-a-systematic-approach-to-web-performance-282b6cf8ae2)
 
[Mihir Mathur](https://twitter.com/mihirmat)
Like anything else, to be successful at web performance, we need a strategy. Read about how Lyft approaches speed to quantify the impact, choose the right initiatives and educate the entire organisation.
 
 
 
# Tools  
 
HTTP/3 check
 
### [HTTP/3 Check](https://http3check.net/)
 
HTTP/3 is near. Use this tool to test whether a server supports the QUIC transport protocol and the HTTP/3 semantics.
 
 
Calibre
 
This email is brought to you by the team at [Calibre](https://calibreapp.com). Our performance monitoring platform helps you deliver stellar user experiences to everyone.
 
 

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