The PIF schema definition is broken into two sections: system, which contains information about root level system objects; and common, which contains definitions of objects that are common throughout the PIF schema.

A file adheres to the PIF schema if it contains a single System object (or one of its derived types) or an array of such objects. While the schema can be used in potentially any hierarchical file format, all examples in this document use JavaScript Object Notation (JSON). Similarly, software packages developed by Citrine Informatics, including pypif and jpif, support only JSON serializations of the schema at this time.