New in Calibre: JavaScript Parse and Compile Runtime Metrics

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

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

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

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. 🤗

Ben Schwarz

Ben is the founder 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.