Mashup is a new genre technology that has recently emerged on the web for creating interactive web applications. The purpose of a mashup is to create a new feature or service for a website or application by combining data or functionality from different sources. It allows the reuse of existing applications for integration of data to create a much more interactive interface. Mashups can be considered as a part of Web 2.0 because they enable high degree of communication and collaboration between applications. Today, many websites are offering programming interfaces (APIs) that allow developers to get at their core information. Mashups use APIs and technologies like XML, AJAX and HTML 5 to build websites that are entirely different from regular sites. That means the new technology is not a rigid traditional webserver model which use typical client and server side methodologies to integrate data for displaying on the browser. Instead, it allows connecting through several API tools to integrate the information or functionality of other services.
Similar to APIs, mashups can be developed for mapping, video & photo functionality, search and shopping and many others. They can be designed for both client and server side based on how the developer wants to manipulate and combine the data. Mashups can be used for designing a visually effective user interface or can connect to other services to import functionality. By using appropriate protocols and design principles, today businesses are able to deliver necessary features to their users quickly and efficiently. Additionally, the development of various web APIs allowed web sources to not only integrate the data from different services but also share it more easily with others. Since mashups are developed using a pre-existing functionality or service, it allows developers to create several such prototypes in a less amount of time than if they were to develop all the components by themselves. Though using mashups for websites is convenient, it also has several downsides because of their dependency on other web sources.