New in Calibre: JavaScript Parse and Compile Runtime Metrics

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Ben Schwarz

November 22, 2017

After a busy November, we’re pleased to let you know that Calibre will now help you understand another vector of web performance.

🏃‍♀ JavaScript runtime metrics

Calibre now tracks parse and compile metrics, broken down by each source.

Runtime execution of JavaScript is what we’ve identified as a major hidden cost for performance on the web. Up until recently, the web performance community hasn’t had a firm grasp on the reporting of these crucial metrics outside of browser dev tools. No more!

If you’ve had a hunch that a particular ad network, tracking script or chat system is slowing down your site, wonder no more. 🎯


📱New test profiles

Switching test profiles for a Calibre snapshot

Test profiles are how Calibre splits up device and bandwidth tests — here are a few small updates to help you test devices more thoughtfully.

First up, when creating a site, the new default profile arrangement will be:

  • Chrome Desktop with an unthrottled network connection
  • Motorola Moto G4, with a 3G connection

Previously we were using an iPhone 6 instead of a Moto G4, but after some reflection, we wanted to provide a default profile that better described a global average smartphone.

There are two new test profile devices to choose from: iPhone 7 and iPhone 8. These more modern phones have extremely fast CPUs and offer near-desktop JavaScript performance.


Help us spread the word about Calibre

Thanks for the shoutout stefan judis 🤝

As always, we’d love to see more companies using Calibre to help make the web a faster place. If you can help spread the word, that’d mean the world to us. 🤗

Profile photo of Ben Schwarz

Ben Schwarz

Ben is the founder and CEO of Calibre. He regularly speaks at conferences worldwide and has been involved in far-reaching Open Source projects as well as web standards. Find him on Twitter or LinkedIn.

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