Python Backlink Monitor Alerts on New and Lost Links Without an SEO Subscription

A developer describes building a DIY backlink monitor in Python, since spotting a lost link otherwise goes unnoticed and SEO suites are priced as monthly subscriptions. Because a backlink sits on someone else's page, the approach relies on licensing a link index through an API, here DataForSEO's Backlinks API, rather than crawling the web or scraping a vendor's interface. The core idea is to compare each check against previous results, reporting only links newly gained or lost since the last run. The author shares three pitfalls: index lag that requires an overlap query window, noise from large domains that suggests monitoring referring domains sorted by rank, and filter behavior in the referring-domains endpoint that can silently drop rows. A sample run of the top 100 links for two sites shows that strong domains often link many times from few referring domains, and that only a minority of links were dofollow.