phantomas
Headless Chromium-based web performance metrics collector
...Metrics can be emitted from the JavaScript code of the page phantomas is run against (thanks to helper functions available in window.__phantomas). Device profiles allow phantomas to emulate mobile or tablet (by setting a proper user agent and viewport). phantomas comes as a CommonJS module that you can use in your nodejs projects. Use grunt to automate daily dev tasks, including your's application web performance.