A doorway page, also known as a gateway page, bridge page, or portal page, is a web page created specifically with the intention of ranking high in search engine results for particular keywords. However, rather than providing valuable content to users, these pages are primarily designed to manipulate search engines and drive traffic to other sites or pages.
Doorway pages violate Google’s guidelines because they essentially deceive both search engines and users. Instead of offering unique and relevant content, doorway pages often contain minimal or duplicated content, and are optimized solely to achieve better search rankings. Google considers this practice as an attempt to manipulate search results and provide a poor user experience.
Google's guidelines aim to prioritize websites that offer quality content and a positive user experience. Therefore, doorway pages are not in line with these principles, and penalties can be imposed on sites using such techniques, including deindexing or lowering search ranking positions.