Mobile MIME Types

Mobile MIME types identify the format of mobile web content: textual mobile markup documents, binary viewable and playable content like ringtones, wallpaper and videos and binary executable mobile applications intended for mobile devices.

Common Mobile MIME Types

Here are the most common mobile MIME types:

MIME Type(s)	File Extension(s)	File Contents	Common Uses
application/vnd.wap.xhtml+xml application/xhtml+xml	xhtml	XHTML-MP markup	Mobile web pages
text/html	html	HTML	Mobile web pages for smartphones
text/css	css	CSS1, CSS2 and Wireless CSS	Cascading style sheets for mobile web documents
text/vnd.wap.wml	wml	WML markup	Lightweight mobile web pages for older or low-end mobile devices
image/vnd.wap.wbmp	wbmp	Wireless Bitmap Image	Black-and-white image format used for older or low-end mobile devices that support only WML in the microbrowser.
text/vnd.wap.wmlscript	wmls	WML Script	Scripting language used with WML
text/vnd.sun.j2me.app-descriptor	jad	Java Application Descriptor	Metadata about a Java ME application for mobile devices. Contains URI to a JAR file that is the mobile application binary.
application/java-archive	Binary	Java Archive	Archive of compiled binary Java class files. Used as packaging format for Java ME mobile applications.
audio/x-midi	mid	MIDI Audio File	MIDI ringtones
audio/vnd.qcelp	qcp	QCELP Audio file	mobile audio
video/3gpp	3gp	3GP Video File	3GP encoding for mobile video files
video/mp4	mp4	MPEG4 Video File	MPEG4 encoding for mobile video files
x-nokia-widget	wgz	Nokia Widget Archive	Home screen widget for Nokia mobile phones
application/vnd.wap.mms-message	mms	Binary MMS in MMS Encapsulation Protocol format	Viewing and sending MMS messages
application/vnd.symbian.install	sis	Symbian installer	Older file format for Symbian application installers
x-epoc/x-sisx-app	sisx	Symbian installer	Newer file format for Symbian application installers

How Mobile MIME Types are Used in HTTP

MIME types are used in several ways during a HTTP transaction between a mobile web browser and web server:

Mobile Web Browser: The mobile web browser sends a list of supported MIME types as the value of the Accept HTTP request header. The Accept request header value advertises the mobile content types supported on the device. Web servers optimized for delivering mobile content use the header’s value (and also a device database) to determine the best content to send in the HTTP response.

Web Server: The MIME type associated with a web document is used as the value of the Content-Type HTTP response header. The web server is configured to associate file extensions of mobile content with mobile MIME types. (Web servers generally do not come pre-configured to support mobile MIME types. The webmaster must manually add the MIME types.) When the web server sends a file to a mobile browser and uses the correct mobile MIME type, the mobile browser client knows how to interpret the file: as a web page, mobile application, wallpaper, ringtone, video, etc.

Web Server Template Languages: The MIME type associated with for a document can be manually overridden using a server-side template language like PHP. Here is a PHP example that uses the built-in header function to override the MIME type for a HTTP response:


header('Content-Type: text/vnd.wap.wml');
?>

It is important to correctly configure mobile MIME types on the web server because the mobile browser uses the MIME type (value of Content-Type HTTP response header) to determine whether the web file is viewed in the browser or by launching phone UI (to set a GIF as wallpaper, etc.) or by launching a native application (playing a video in the video player, etc).

Read more about web server configuration for details about adding MIME types into Apache and IIS web servers.