rel="next" and rel="prev" tags are
<link> elements used to indicate search engines that multiple URLs are part of a paginated series. This tool allows you to quickly check if these tags are correctly implemented on a paginated series.
Learn more about pagination and SEO
In instances of paginated series, rel="prev" and rel="next" tags should be used in order to consolidate equity of individual pages into one URL and resolve eventual near-duplication.