Advanced Customization > Info*Engine User’s Guide > Info*Engine Architecture > Interacting with Info*Engine > External Applications Processing XML over HTTP (or HTTPS)
  
External Applications Processing XML over HTTP (or HTTPS)
Info*Engine comes pre-installed with the IE servlet that can be used to invoke Info*Engine tasks directly over HTTP or HTTPS. When tasks are invoked through the IE servlet the Info*Engine Virtual Database (VDB) is rendered as XML in the response.
Alternately, Info*Engine tasks can condition the data in the response by writing binary data in place of XML or by transforming the Info*Engine VDB to an alternate XML representation of their choosing.
By using the IE servlet simple HTTP or HTTPS clients (written in any language), an application can issue requests to send and retrieve data from Info*Engine.
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If your site is using form-based authentication, programmatic clients attempting to access the IE servlet must use the /protocolAuth URL prefix. For example:
http://<host>/Windchill/protocolAuth/servlet/IE
For more information about form-based authentication, see Form-based Authentication.