Online-to-offline (O2O) is a term that is used in digital marketing to describe systems enticing consumers within a digital environment to make purchase of goods or services from physical businesses.  In this system, there is an application-to-application payment which means transferring money from customer’s account to seller’s account through the application. Commission to settlement agency and card company is decreased since money is transferred to seller’s account directly. Thus, application-to-application payment system is an important component in the mobile payment and plays a key role in online-to-offline commerce. For that, the purpose of this bachelor thesis is to develop a pre-order system, which help client buy the food easily using an application.
To implement this system, there are several tasks such as installing software tools, development configuration settings, design and implement the application. These steps are carried out by a team, I contributed some parts of system development which includes the design of the database, the implementation of login and join, withdraw and charge balance functions at server side, condition check and at client side, communication between server and application. The most important tool is the Spring boot framework for server development. This framework help developers who do not have server development experiences to implement server-side features easily.
With this framework, I could make a system which can show the list of stores and foods. And selected foods could be paid by using the balance of virtual account. By using the QR data, clients can receive their food easily.