1. HTTP Request: Header, Request Type, Payload, Endpoint. 2. HTTP reponse: Header, Payload, Status Code. 3. JSON & XML 4. A JSON file is like a matrix that in one column has the keys and the other one contains each key's value. 5. Code: HttpRequest request = new HttpRequest(); request.setMethod('GET'); request.setEndpoint('https://735ef563-176d-431c-85ce-2cc07056ef03.mock.pstmn.io/payments/link'); Http http = new Http(); HttpResponse response = http.send(request); Map<String, Object> parsedBody = (Map<String, Object>) JSON.deserializeUntyped(response.getBody()); Map<String, Object> parsedTransaction = (Map<String, Object>) parsedBody.get('transaction'); Map<String, Object> parsedDetails = (Map<String, Object>) parsedTransaction.get('details'); String ip = (String) parsedDetails.get('IP'); System.debug(ip);