Since first introducing the Web Vitals initiative in May of 2020, we on the Chrome team have received a lot of great questions and feedback about the program.
Perhaps the topic we've received the most questions about, which is also probably the hardest question to answer, is how to measure Core Web Vitals in a single-page application (SPA), as well as how SPA architectures affect Core Web Vitals scores.
These questions are hard to answer because the problem is quite nuanced, so in this post we're going to do our best to answer the most common questions, providing as much detail and context as we can.
Before getting into specifics, though, it's important to state that Google does not have any preference as to what architecture or technology is used to build a site. We believe that SPAs and multi-page applications (MPAs) are both capable of delivering high quality experiences to users, and our intention with the Web Vitals initiative is to provide metrics that measure the experience independent of the technology. While this is not possible in every case today (due to limitations in the web platform), we are actively working on closing those gaps.