An apparatus, system, and method are provided for defining a web services interface for an MFS-based IMS application. The apparatus, system, and method include a parser that parses an MFS-based IMS source file into one or more Message Input Descriptions (MIDs) and one or more Message Output Descriptions (MODs). A prompt module prompts a user for a device type and device feature combination supported by the MIDs and MODs. A display module displays a MID list and a MOD list and automatically selects one or more MODs associated with a user-selected MID. An assembly module assembles the user-selected MID, the associated MODs, and the user-selected device type and device feature combination into a web services interface.