MIME stands for Multipurpose Internet Mail Extensions. It is a way of identifying files on the Internet according to their nature and format. For example, using the Content-type header value defined in a HTTP response, the browser can open the file with the proper extension/plugin. MIME types were originally created for emails sent using the SMTP protocol. Nowadays, this standard is used in a lot of other protocols, hence the new naming convention Internet Media Type.

Our web servers have a list of the pre-defined most common MIME types, however sometimes you may need to add your own MIME types. See the full MIME Types List if needed.

Windows 2003

Submit a free Add Custom MIME Type service request via the Extended Services portal and specify the files extension and the corresponding MIME type that needs to be added. You can check with the documentation for your product to find out what MIME type should be set for it.

Windows 2008

  1. Open IIS Manager
  2. In Features View, double-click on MIME Types

  3. In the Actions pane, click on Add
  4. In the Add MIME Type dialog box, type a file name extension in the File name extension text box and a MIME type in the MIME type text box
  5. Click OK


You can configure MIME types using the .htaccess file. When you configure MIME types in your .htaccess file, you associate file types with a specific application or action. For example:

AddType text/html htm0

'AddType' specifies that you are adding a MIME type. The second part is the MIME type, in this case text or HTML, and the final part is the file extension, in this example 'htm0'.

A common issue with .mp3 or .swf files not playing can be resolved with the following text:

AddType application/x-shockwave-flash swf

Note: application/octet-stream type identifies files that are not associated with a specific application. A server or application should not indicate a content type of such files, as it may be incorrect, but rather, should omit the type in order to allow the recipient to guess the type.