The MIME type application/smil is used to denote the presence of Synchronized Multimedia Integration Language. This MIME type is categorized as "application".

Synchronized Multimedia Integration Language files carry the extension SMI. The language is usually known by its abbreviated form � SMIL. SMIL is an XML markup language that is recommended by the W3C (World Wide Web Consortium) for describing multimedia presentations. It is used to define various aspects of multimedia presentations such as timing, animation, layout, visual transitions, embedding, etc. SMIL is used for the presentation of text, video, image and audio type media items, other SMIL presentations. SMIL also allows Files from multiple servers are to be presented.

SMIL markup is written in XML and is similar to HTML in certain ways. W3C made SMIL 1.0 a recommendation in July 1998. SMIL 2.0 achieved this in August 2001. SMIL 2.0 introduced a more modular language that led to the integration of SMIL semantics into other languages based on XML. SMIL 2.1 achieve the recommendation in December 2005 and SMIL 3.0 achieved it in December 2008.