Now a days the data synchronization based on Web Services. It will allow software applications to work on both configurations "Online" as well as “Offline”, in the absence of the network. Reliability of the system is always given higher priority whenever multiuser system is been developed. Involvement of the end users in this process is very important. The aim of this paper is to make a reliable system with no faults to the end user. Thus, information about reliable software applications is important. It will be hard to achieve consistent level of reliability for every complex system that includes multi user and data manipulations. If the connection is lost, system works with local server, that is it saves new data in local server which are not in central server and in this case the synchronize component should synchronize data with data centre when connection is present. Thus, we can increase the reliability to the end users.