History of backlink indexing

Overview

Getting a page crawled has always been easy for its owner and hard for everyone else. The history of backlink indexing is a series of workarounds for that asymmetry, each of which worked for a while and then lost value as search engines adjusted. This entry covers the methods for which there is documentary evidence and avoids dates that no primary source supports.

Era 1: pings and submissions

The earliest discovery shortcuts were built for site owners. Blogs announced new posts to ping servers, which passed update notices on to search engines and aggregators. The Sitemaps protocol, which Google says was introduced in 2005, let owners list their URLs and announce a sitemap with an unauthenticated HTTP "ping".

Because neither mechanism checked who was sending, link builders used them for pages they did not own: ping a guest post, ping a profile page, submit a sitemap containing other people's URLs. Ping-based tools remain the basis of many free backlink indexers.

The search engines eventually withdrew the anonymous channels. Bing removed anonymous sitemap submission on May 13, 2022, saying it "was often subject to misuse by spammers." Google followed on June 26, 2023, announcing that its sitemap ping endpoint would stop functioning in six months because "the vast majority of the submissions lead to spam."

Era 2: link pyramids and automated link pages

When pings carried less weight, the common approach became making the target page discoverable through links Googlebot would follow. Tools generated large numbers of low-quality pages (social bookmarks, profile pages, auto-built blogs) linking to the backlinks a user wanted indexed. Arranged in tiers, with the cheapest links at the bottom pointing at better links above them, the structure was called a link pyramid. The modern, more restrained form is described under tiered links.

Google announced a webspam algorithm update on April 24, 2012, aimed at sites using techniques such as link schemes. Its current spam policies list "using automated programs or services to create links to your site" as a link scheme, which describes the bottom layer of a pyramid. Practices built on mass-generated links became a liability for the pages they were meant to help, and the question of whether indexing tools are safe still turns on this point; see are backlink indexers safe.

Era 3: the Indexing API

Google launched the Indexing API on June 26, 2018 for job posting pages and extended it to livestream pages on December 5, 2018. It let an owner push a URL notification and receive a quick response, and Googlebot often visited soon after.

SEO practitioners noticed that publish calls were accepted for any URL in a verified property, and the technique spread to backlinks through scripts and some commercial services, frequently using many service accounts to multiply quota. Google's current documentation addresses each element in writing: the API "can only be used to crawl pages with either JobPosting or BroadcastEvent embedded in a VideoObject," quota beyond testing requires approval, spam policies apply, and callers must not circumvent limits "such as by using multiple accounts." Google has not published a date for any enforcement change, so none is given here. The current rules are summarised in Google Indexing API and backlinks.

Era 4: managed crawl services and verification

What remains is the model most paid tools use today: a service accepts URLs on any domain, generates crawl signals by its own means, and in some cases reports or checks the outcome. The mechanics are described in how backlink indexers work, and the category is defined in what is a backlink indexer.

Two shifts mark this period. Vendors began separating crawl from index in their promises, since a crawl can be caused but an index decision cannot. And independent verification became a product feature, because users had learned not to trust submission reports alone; see verifying backlink indexation. Pricing also diversified into credit, refund and subscription models, compared on backlink indexer pricing models.

Meanwhile owner-side discovery moved on without Google: the IndexNow protocol lets owners notify Bing, Yandex and other participants, but Google is not among them (IndexNow and backlinks).

Timeline

Where IndexChex sits

IndexChex, the publisher of this wiki, belongs to the fourth era. It states that its methods do not use link pyramids or spam networks, it does not use the Indexing API, and it pairs submission with an index checker so results can be verified in the same account.