How this checks indexing
This runs a site: search for the domain or URL you enter through Google's Custom Search API -
if any results come back, the page or site has at least some content indexed by Google. This is the same
underlying signal behind the classic manual "site:yourdomain.com" search trick people have used for years,
automated here and returned as a clear indexed/not-indexed result instead of a raw results page to read
through yourself.
Why this is a public signal, not an authoritative one
Because this works for any site without logging in or owning it, anyone can check any domain's indexing status. That's also its main limitation: it's a general public signal, not the page-specific, authoritative answer Google itself gives the verified owner of a site. If you own the site in question, Google Search Console's URL Inspection tool goes much further - it tells you not just whether a page is indexed, but why a specific page might be excluded if it isn't.
What "indexed" and "not indexed" actually mean here
An "Indexed" result means Google returned at least one real result for a site: search on that
domain, and the tool shows you a sample of those indexed URLs. A "No indexed pages found" result doesn't
necessarily mean the site is banned or broken - it commonly just means the site is very new, very low-traffic,
or was only recently submitted and hasn't been crawled and indexed yet.
What to do if your own site shows as not indexed
Submit your sitemap through Google Search Console if you haven't already, use the URL Inspection tool to
request indexing of specific important pages, and check that nothing in your robots.txt or page-level
noindex tags is accidentally blocking the pages you expect to be indexed.