What is a Gateway Page?
A gateway page is a webpage that appears in search results for a keyword but then redirects the visitor to a different content when clicked. They are also called entry or doorway pages.
Gateway pages are created to rank well in search engine results for a particular keyword or set of keywords. However, they do not offer value and will redirect visitors to the other webpage instead.
Google considers gateway pages as webspam. They offer no value to visitors and are just another attempt to manipulate search rankings. For this reason, it is best to avoid creating them as they could earn you a manual action if discovered.