In today’s public market Mobile phones has become a part of everyday life. The introduc-tion of Smart Phones has created a new market for services and applications for the Smart Phones. Many of these users would benefit of customizing their own services to fulfil their needs. This can be achieved with end-user service composition. End-user service composition enables the user to compose their own services from already existing components to provide val-ue added services. In this Master Thesis a service composition tool consisting of the two applica-tions Easy Composer and EasyDroid is presented. The idea of the tool is that ordinary people without technical background will be able to quickly compose their own services in a simple manner. The existing tool has been in development for a while, but still lack some sufficient quality in terms of usability and utility for ordinary people to make use of it. Utility means what the tool can be utilized to, and usability means the user-friendliness and usefulness. In this Mas-ter Thesis a new system has been made for the service composition tool. The Easy Composer application has been discarded and new web based GUI has replaced its functionality. In addi-tion, the EasyDroid application has been remade and a new server side has been developed. Fur-thermore, the communication between the different parts has been improved. The usability and utility of the previous system has been considerably improved in the new system. In other words the existing functionality has been made more user friendly and new functionality has been added to the tool. The goal is that the service composition tool would have the sufficient quality and novelty for ordinary users to embrace it.