XML-binary Optimized Packaging (XOP) is one of a related pair of
specifications that define how to efficiently serialize XML Infosets
that have certain types of content.
XOP defines how to efficiently serialize XML Infosets that have certain
types of content by:
- Packaging the XML in some format. This is called the XOP package. The
specification mentions MIME Multipart/Related but does not limit it to this
format.
- Re-encoding all or part of base64binary content to reduce its size.
- Placing the base64binary content elsewhere in the package and replacing
the encoded content with XML that references it.
XOP is used as an implementation of the MTOM specification, which defines
the optimization of SOAP messages. Because these two specifications are so
closely linked, they are normally referred to as MTOM/XOP.
The specification is published by the World Wide Web Consortium (W3C) as
a W3C Recommendation XML-binary Optimized Packaging (XOP):