What keyword cannibalization is and why it hurts
Keyword cannibalization happens when two or more pages on the same site are optimized for the exact same target keyword, effectively competing against each other rather than against outside competitors. This tends to happen gradually and unintentionally — a blog grows over months or years, and a new post gets written on a topic that's similar enough to an older post that both end up targeting the same core phrase, without anyone noticing until both pages are live and indexed. Rather than the site's overall authority for that topic being concentrated in one strong, comprehensive page, it gets split across two or more weaker, competing ones.
This tool takes a simple list of pages — a URL, an optional title, and the specific keyword each page is meant to target — and checks for any keyword that appears as the target for more than one page. It's deliberately a straightforward exact-match check on the keyword field you provide, since accurately detecting cannibalization from ranking data alone would require live search visibility data that a client-side tool can't access; this version relies on you providing an honest, accurate target keyword for each page, which is information only you have.
Why this matters even without live ranking data
The most valuable part of catching cannibalization often isn't a search engine's ranking behavior — it's simply the act of explicitly listing out every page's intended target keyword in one place, since that's rarely done systematically as a site grows. Many cannibalization problems are found the moment someone actually writes down what each page is supposed to be about and compares the list side by side, well before checking how either page performs in search results. This tool is built around that workflow: the value is in the deliberate listing and comparison, with the overlap detection simply automating the "did I already target this?" check across however many pages you're tracking.
What to do once you've found an overlap
When two pages are found targeting the same keyword, the usual fix isn't to delete one outright, since both may contain content worth keeping. Common approaches include consolidating the two pages into one more comprehensive piece and redirecting the weaker page to the stronger one, clearly differentiating the two pages around a more specific angle or sub-topic so they each target a genuinely distinct keyword going forward, or, if one page is clearly outdated and the other is its natural successor, retiring the older page with a redirect to the newer one. Which approach fits depends on whether the two pages genuinely serve different reader needs or are really just two versions of the same intended content.
Keeping this list up to date
Since this tool works from a list you maintain yourself rather than crawling your site automatically, it's most useful as a living reference updated whenever a new page is planned — checking a new page's intended keyword against the existing list before it's even written is a cheap way to catch cannibalization before it happens, rather than discovering it after two competing pages are both already live and indexed.