your client will need to request to the server, for data. on the request you can include data like API Keys when the request arrives at the server, will provide back with a response if it was successful or not, and provide you with data (JSON, XML, etc) – on the very simple form, RESTful can we thought of a way to get data.
JSON is a simple standard for data delivery in the restful model, JSON has been used to exchange data between applications written in all of these programming languages.
this source https://restfulapi.net/json-vs-xml/ provides some more insights.
XML is a data format, AND it is a language also. It has many powerful features which make it much more than simple data format for data interchange. e.g. XPath, attributes and namespaces, XML schema and XSLT etc. All these features have been the main reasons behind XML popularity.
JSON was not designed to have such features, even though some of them are now trying to find their places in the JSON world, e.g. JSONPath.
Simply put, XML’s purpose is to document markup. Always prefer to use XML, whenever document markup and meta-data is an essential part of data and cannot be taken away.
curl -X GET 'https://rest.messagebird.com/reporting/sms?periodStart=2018-04-01T00:00:00Z&periodEnd=2018-04-30T00:00:00Z&periodGroup=month&filterBy[originator]=OmNomNom&filterBy[originator]=BeautyBird&groupBy=originator' -H 'Authorization: AccessKey test_euSTWsGvjp' -H 'Accept: application/json'