When working with PDFs, I've run across the MIME types application/pdf
and application/x-pdf
among others.
Is there a difference between these two types, and if so what is it? Is one preferred over the other?
I'm working on a web app which must deliver huge amounts of PDFs and I want to do it the correct way, if there is one.
Best Solution
The standard Media Type (formerly known as MIME types) is
application/pdf
. The assignment is defined in RFC 3778, The application/pdf Media Type, referenced from the Media Types registry.Media Types are controlled by a standards body, The Internet Assigned Numbers Authority (IANA). This is the same organization that manages the root name servers and the IP address space.
The use of
x-pdf
predates the standardization of the Media Type for PDF. Media Types in thex-
namespace are considered experimental, just as those in thevnd.
namespace are considered vendor-specific.x-pdf
might be used for compatibility with old software.