Before spending money on an indexer, I'd diagnose why the page isn't indexed — because indexing is really a two-step problem: discovery, then inclusion. Paid indexers only help with step one, and only sometimes.
1. Confirm the page is crawlable and the link exists in a form Google can actually see. Fetch the page and check view-source: JS-injected links, pages behind robots blocks or logins, and links tagged nofollow/UGC/sponsored will never index no matter what tool you throw at them. This alone explains a surprising share of "indexing" failures.
2. Give Google a free crawl path first. The most reliable cheap method is the one IM Dude mentioned: link to the unindexed page from an indexed page you control, then request indexing of your own page in Search Console. An RSS feed or a simple HTML sitemap page on your own property works the same way. This tends to outperform paid ping services because it gives Google a genuine discovery signal instead of noise.
3. Only pay for tier 1s. CaptchaSolver8 makes the right point — indexing tier 2 and 3 at scale is usually money for nothing. Crawled pages can pass value even before the index entry shows up; the index entry matters most for links pointing directly at your money pages.
One caution: Google's Indexing API officially supports only job posting and broadcast event pages. Using it to force-index backlink pages is against their documented policy, and I've seen API access get pulled for it. For pages you own, use the URL Inspection tool in Search Console instead.
My order of operations: verify crawlability first, then a free crawl path from your own indexed pages, and only then a paid indexer for the stubborn tier-1 links.
