Can I use the Google Indexing API for normal pages?
Google says its Indexing API can only be used for pages with job posting or livestream video structured data. Every request goes through spam detection, and Google says abusing it, including using several accounts to get around quotas, can get access revoked. For product pages, docs, blog posts, and everything else, Google points you to sitemaps and Search Console.
Source: Google Indexing API quickstart