In 2016 at Google I/O, Lighthouse was launched to improve the quality of website and PWA apps. Lighthouse is an open-source, automated tool for auditing and improving the quality of your web apps. One year later, Eric Bidelman and Brendan Kenny walked through what's new in Lighthouse in 2017 and how it's evolved into a companion for modern web development. This video covers various aspects of Lighthouse in different environments (Node CLI, Chrome DevTools, WebPageTest, headless Chrome) and ways you can extend Lighthouse by authoring custom audits to run against website.