Hi, 
There is so much lag between request and response even after using 'Prefer': 'respond-async' in the header. My request and response fields are as follows. 
Request structure 

Request URL is https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/ExtractRaw 

Method is POST 

Params are {} 
body is {"ExtractionRequest": {"@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.TickHistoryTimeAndSalesExtractionRequest", "ContentFieldNames": ["Quote - Ask Price", "Quote - Ask Size", "Quote - Bid Price", "Quote - Bid Size", "Quote - Sequence Number", "Quote - Exchange Time", "Trade - Exchange Time", "Trade - Price", "Trade - Sequence Number", "Trade - Tick Direction", "Trade - Volume"], "IdentifierList": {"@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.InstrumentIdentifierList", "InstrumentIdentifiers": [{"Identifier": "SX7", "IdentifierType": "Ric"}], "ValidationOptions": {"AllowHistoricalInstruments": true}, "UseUserPreferencesForValidationOptions": false}, "Condition": {"MessageTimeStampIn": "GmtUtc", "ApplyCorrectionsAndCancellations": false, "ReportDateRangeType": "Range", "QueryStartDate": "2017-10-26", "QueryEndDate": "2017-11-05", "DisplaySourceRIC": true}}} 

headers are {'Prefer': 'respond-async', 'Accept-Charset': 'UTF-8', 'Content-Type': 'application/json', 'Authorization': 'Token valid Token'} 

Response I got is 
Headers are {'Set-Cookie': 'DSSAPI-COOKIE=R2154578860; path=/', 'Status': 'InProgress', 'X-App-Id': 'Custom.RestApi', 'Content-Length': '0', 'X-App-Version': '11.1.527.64', 'Expires': '-1', 'Date': 'Fri, 07 Jul 2017 18:21:57 GMT', 'Pragma': 'no-cache', 'Server': 'Microsoft-IIS/7.5', 'Cache-Control': 'no-cache', 'Progress': '', 'X-Request-Execution-Correlation-Id': '25dde56c-d602-465d-972c-8ac949c46e8a', 'Location': "https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/ExtractRawResult(ExtractionId='0x05c925be9fcb3036')"} 
Status code is 202 

But it takes like 30 seconds to get the response back even after using respond-async. Could you please tell me how to decrease the time taken?