Construct is a Python library for the construction and deconstruction of data structures in a declarative fashion. In this context, construction, or building, refers to the process of converting (serializing) a programmatic object into a binary representation. Deconstruction, or parsing, refers to the opposite process of converting (deserializing) binary data into a programmatic object. Being declarative means that user code defines the data structure, instead of the convention of writing procedural code to accomplish the goal. Construct can work seamlessly with bit- and byte-level data granularity and various byte-ordering.