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 and CEO of Calibre. He uses his experience in far-reaching Open Source projects and web standards to build tools for a better, more accessible web. Find him on Twitter or LinkedIn.