What format does a RESTful service use for requests and responses?

In RESTful services, the primary format used for data interchange is JavaScript Object Notation (JSON). One of the key characteristics of REST is its emphasis on lightweight and efficient data transmission, which JSON provides.

JSON is easily readable for humans and can be parsed and generated by machines quickly, making it the preferred choice for RESTful services. Unlike XML, which often involves complex schemas and can lead to bulkier payloads, JSON allows for a more streamlined and less verbose data format.

Moreover, REST does not require a strict contract for the data being exchanged, which means developers can easily adapt and evolve their services without being hindered by formal agreements. This flexibility is crucial in many applications where agility and rapid development are essential.

Other formats like XML with schemas, SOAP, and HTML are not typically associated with RESTful services due to their overhead and complexity compared to the simplicity and streamlined nature of JSON.