#### article

## Learn about why to track Core Web Vitals
A few weeks ago, Google announced a new initiative dubbed Web Vitals. We explain what Core Web Vitals metrics are, why it’s essential to track them, and how they affect your sites’ ranking and user experience.
[]()[Everything You Have to Know About Core Web Vitals →](https://calibreapp.com/blog/core-web-vitals)
#### article

## Discover the near future of fast HTTP
[Mark Nottingham](https://twitter.com/mnot) explains the benefits of a new specification surrounding HTTP headers (and trailers). Structured Fields is at final stages of development and is supposed to ease some of the pains of HTTP headers and introduce possible performance gains on networking level.
[]()[Improving HTTP with structured header fields →](https://www.fastly.com/blog/improve-http-structured-headers)
#### Talk

## Make your apps visually accessible
In a short, 15-minute talk, [Drew Haas](https://twitter.com/DrewHaas) showcases how you can build more accessible iOS and Mac applications. Drew provides code snippets and examples of specific approaches you can use in ensuring your apps are accessible to all.
[]()[Make your app visually accessible →](https://developer.apple.com/videos/play/wwdc2020/10020/)
#### browsers

## Start using WebP images in Safari
WebP is a performant image format that yields significant size savings compared to JPG and PNG. After ten years since its announcement, WebP will be supported in Safari on desktop and mobile devices.
[]()[Safari 14 Beta Release Notes →](https://developer.apple.com/documentation/safari-release-notes/safari-14-beta-release-notes#Media)
#### tools

## Compare your metrics to CrUX data
[Rick Viscomi](https://twitter.com/rick_viscomi) and [Shane Exterkamp](https://github.com/exterkamp) teach how to use the recently released Chrome UX Report API to import field user experience data. With the new API, you will be able to compare your Core Web Vitals measurements to CrUX data and more.
[]()[Using the Chrome UX Report API →](https://web.dev/chrome-ux-report-api/)
#### new in calibre

## What’s Calibre released last month
📚 [**Release Notes: May**](https://calibreapp.com/blog/release-notes-may-2020)
Here’s our monthly roundup of what was released in May: Lighthouse 6 support, improved Main Thread Execution Timeline and more.
🆕 **Performance Budgets 2.0:** We completely redesigned how speed budgets work in Calibre. Now, you’re able to set thresholds based on historical data and industry recommendations. Create your budget dashboard today!
[]()