Kent C Dodds made a claim on Twitter (X) that the “biggest performance problems are probably backend, not frontend related.” Is this true? Some websites have slow backends, for sure. Others have slow frontends. A few unfortunate sites are slow in both. But as of today, right now in 2023, which is the bigger performance problem for most teams, the frontend or the backend? I wanted to explore it with some real data from the web.

Interaction to Next Paint (INP) is a newer addition to the Core Web Vital metrics intended to measure how real users perceive the responsiveness of modern web applications. Web Vitals Measurements like INP are becoming increasingly important as web applications and SPA’s run more JavaScript on the client side.