Say you want to send a list of consumer records to another microservice over network via JSON. There are three concepts at play in this process: A logical value, which is how we humans treat the data. In this example, this would be “a list of consumer records”. This description does not specify how it’s represented in the computer, or whether you’re using a computer at all. A data type, e.g. std::vector . The purpose of a data type is two-fold: a) it denotes a specific runtime representation of the logical value in computer memory, b) it provides an abstraction so that you can work with the logical value without thinking about this implementation detail. A serialization format, here JSON. It denotes an alternative, byte sequence-oriented representation of the logical value, but does not provide an abstraction layer, since you cannot directly work with the records encoded in the JSON string.