1. A computer program product, comprising: a computer readable storage device to store a computer readable program, wherein the computer readable program, when executed by a processor within a computer, causes the computer to perform operations for simplifying an extensible markup language (XML) schema, the operations comprising: identifying data in an instance specification as variable or fixed, wherein the instance specification corresponds to a complex XML schema; determining a set of types comprising the variable data, wherein the set of types conforms to a structure of the complex XML schema; capturing the set of types as metadata annotations associated with the instance specification; and generating a simplified XML schema for the instance specification using the set of types.