Next.js is the more common of the two in our index: it runs on 4,680 websites against 3,361 for Vue.js, and 28 sites use both. Counts come from real scans, not vendor claims.
Next.js is a React framework for developing single page Javascript applications.
Vue.js is an open-source model–view–viewmodel JavaScript framework for building user interfaces and single-page applications.
28 sites run both Next.js and Vue.js. That is 1% of the sites using Vue.js, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.