Gadget attributes are case-sensitive keywords used to define characteristics of gadgets. They are stored as the fourth-level subscript descended from the parent window's name (see Example 5.1 for the syntax). The MWAPI specification defines fifty attributes available for use by gadgets, and permits the use of application- and implementation-defined keywords. Application attributes, which provide the programmer with a means to store additional information within the definition of a gadget, must begin with the letter "Y."

Implementation attributes are keywords defined by the vendor of an MWAPI implementation. The character "Z" is reserved for the first letter in the name of implementation-defined attributes. A hierarchy exists in the scope and portability of attributes:those defined in applications have the scope of (and are portable to the extent of) the application where they are specified. Implementation attributes have the scope of the entire implementation and may not be portable. Those attributes specified by the MWAPI standard are guaranteed portable among all conforming implementations and platforms. Table 5.3 list the attributes available to gadgets categorized by function.