What is a MPP file?
A file with MPP extension is Microsoft Project data file that stores information related to project management in an integrated manner. It is proprietary file format developed by Microsoft as file format for Microsoft Project (MSP) which is a project management application software. Besides MPP, MSP supports other file formats as well like project XML schema. Several APIs and applications provide the facility to convert MPP file format to others. Microsoft now has online Project Server where project management files can be uploaded for collaboration by multiple users.
MPP File Format
Microsoft developed and published MPP as binary file format and its specifications have not been made public by Microsoft till date. The internal file structure and details are, hence, not available for developers. There are several APIs available online that support reading/writing to MPP files, but 100% accuracy is never achieved. Microsoft has introduced several features to its project management application over the span of time and so has the features contained by the MPP file format.