A pagination checker looks at the tags that connect the pages of a series, such as page 2 of a blog archive or a product category. Enter a URL and this tool fetches the page and shows whether it has <link rel="prev">, <link rel="next"> and a canonical tag, with the URLs the pagination tags point to.
It warns when a rel=next or rel=prev link uses a relative path instead of a full URL, and it notes when a page has no pagination tags, which is normal for pages that aren't part of a series. Each page in a series should normally have a self-referencing canonical (page 2 points to page 2, not to page 1), so the posts or products listed on deeper pages stay discoverable.
Google said in 2019 that it no longer uses rel=next and rel=prev as an indexing signal. It finds paginated pages through normal <a href> links instead, so crawlable links to the next and previous pages matter more than the tags. Other search engines may still read the tags, and they do no harm.
Limits: the tool checks one page. It doesn't follow the series or confirm that the linked pages return 200, and it checks that a canonical exists, not where it points. It reads the HTML before JavaScript runs, so for infinite-scroll pages check separately that real page links exist.
