Private indexers usually combine multiple techniques rather than one magic method. Self building something effective takes solid infrastructure and constant maintenance cause method die quickly. If it's just for your own links, should try submitting via Search Console and earning natural crawls from good pages tends to be more stable long-term than trying to force it dude
If it's for ranking your own sites don't bother; just submit your links on GSC.
Sure thing, and my first port of call would be to see if the backlinking page is actually indexed and not just the home page of the website. If it isn't indexed, I'd first consider internal links and if the page is being crawled.
It feels more sensible to me if you should first conduct research whether the backlinks page are indexed or not before creating a tool for this job becuz an index page does not mean finding a backlink. maybe you will find out that some sort of pattern exist when it comes to the sources.
A quick heads up that the Indexing API from Google is mostly meant to be used for job listings and live streaming pages, not blogs in general. Normal links should use GSC URL Inspection and an organized internal linking strategy.
really honestly, I feel that I would start off working with the indexed pages in terms of their backlinks. sometimes, even after several ping checks, those link can get unindexed. the live, crawl, and index checks have to be performed independently so as to know what references are to be relied on. have you explored the indexes yet?
i couldd begin with crawl access and checking if urss backlinks are even crawlable building an indexer is one thing having search engines trusts and index those links is another tbh
The methods used by most indexer tools are usually quite similar; for example, crawling, discovery signals, and making links accessible.
