Next.js is built on React. The difference a scanner sees is often how a site delivers content: useful HTML and links immediately, or an app shell that JavaScript fills later. Either implementation still needs correct public URLs and navigation.
Compare responses instead of framework labels
Take one equivalent public route from each site. Look for its heading and navigation in the HTML response, then inspect the sitemap. If one site lists fifty URLs and the other lists none, a sitemap-first scanner will naturally start with different information. That observation does not establish that all React sites have an SEO problem.
Check the count before checking the score
Discovery reports the URLs the scanner found. The audit scope is the subset you choose or your plan allows. A free homepage audit can inspect one page even when discovery found many. Keep these two counts separate when troubleshooting.
- Run a fresh discovery after publishing a sitemap or navigation change.
- Check whether URLs came from the sitemap, homepage, or script hints.
- Choose all discovered pages on an eligible account if you want a multi-page audit.
Fix the delivery problem in your current stack
If public pages already deliver readable HTML, focus on missing links, route availability, or sitemap coverage. If they only deliver an empty shell, evaluate SSR or prerendering for those routes. A framework migration is a larger decision and is not required just because one scanner found a single page.
Compare both sites with the same SiteReadyFor.SI workflow
Run discovery for each site and record the source and page count. Use the report’s visible-content findings to locate pages worth inspecting. Script-derived links are hints rather than a complete route inventory; a maintained sitemap is easier to verify for dynamic content.