What is Document type?
Documents in a search index are divided into different document types based on their different schemas. For example, imagine a website that has blog entries, product listings, and support articles all under one domain. A well structured search engine will index these documents as different document types, which will allow users to sort results on an SERP by content type.
In Swiftype
Swiftype API users can create different document types (further information available in the documentation), while crawler based engines can achieve the same effect using Swiftype meta tags.