Why your Next.js site is slow (and it isn't React)

Every quarter a client forwards us a Lighthouse score and blames React. It's almost never React.

1. Uncached CMS fetches at request time App Router server components make it trivially easy to fetch data inside a component that runs on every request. If your CMS client doesn't cache and your page has six components each fetching the same story, you're making six network round-trips on every page load.

2. Images served at wrong dimensions The Next.js Image component handles resizing, but only if you give it accurate width and height props. CMS-driven images often have dynamic dimensions.

3. Third-party scripts on the main thread Analytics, chat widgets, and A/B testing SDKs loaded synchronously block the main thread. Move everything to next/script with strategy=lazyOnload.