Create server side API to get data from mobiles

Before you bid, please carefully read my requirement. I have an Android app, installed on around 150 mobiles. During the night each mobile saves data entries locally [around 70 entries of date,time and location name] . In the morning, they connect the device to WIFI and sync the data to my ORACLE server. In the app i have called my API which sends data. Now I want this system to move to Shared Linux Hosting with hostgator. For that i want you to design a data syncing API, so that we have a minimum of server calls, minimum of server load and easily the data is synced. You should know how we currently are doing this - First call [from mobile to server] - Each data entry from mobile sent to server Second call [from server to mobile] - checks same entry in mobile saved by server and then deletes from mobile. So if a mobile has 70 entries, the above loop will run 70 times choking my server. I want you to design a API with minimum server load, i will calls and data should not be lost. Please prefix API before your bid so i will get to know who made a bid after reading till here. We will do if any changes required on the app side.