expert Magento api developer

Hello, we are searching for a magneto expert to help in api for an android application for our website hese are the missing apis in the App with their expected parameters and response, any modifications on these parameters are welcomed: 1-checkout api:- method: POST params: {"userID":"14"} response: {"error":false, "message":"cart checkout successful"} {"error":true, "message":"cart is empty"} {"error":true, "message":"any other error"} 2-change address:- method: POST params: {"userID":"14", "telephone:"01227786137", "address":"96 sakr new maadi cairo", "city":"cairo", "isBilling": true} response: {"error":false, "message":"address updated successfully"} {"error":true, "message":"any other error"} 3-add address:- method: POST params: {"userID":"14", "telephone:"01227786137", "address":"96 sakr new maadi cairo", "city":"cairo", "isBilling": true} response: {"error":false, "message":"address added successfully"} {"error":true, "message":"any other error"} thanks