Web based online games increases today on the game market. A number of games have the last years expanded to several hundred thousands of users. To render possibility for this kind of games, a database, a script language and possibly a game engine. We have created a game where the users control and rule a city with a web browser. The goal of the game is to control the biggest and most healthy city. The view that the user sees in the web browser is just one of the parts that together interacts and constitutes the game. For script language, PHP is used. PHP which script engine generates the text and the images the user sees. The PHP-code also manages the actions the user performs. All game information about the cities is stored in a database, which is updated by the PHP-code. The database is a MySQL-database. There is also a game engine written in C++. The engine is constantly running and updates the game information at specific points of time. PHP has good built-in support for MySQL access, while in C++ there is a special API, MySQL++, which can be used to access the MySQL-database. All the pages in the game have the same base structure and look, so that the users will feel safe and easily can navigate through the game. This report describes the development of an online game called BigCity. We are relatively satisfied with the game. To a great extent, the game follows the specification, see appendix Fel! Hittar inte referenskälla., which was composed in the beginning of the bachelor project. All the major parts we wanted to implement, except the trade agreement-part have been implemented. However, the game does not feel quite finished, some more functionality would probably be necessary. Sometimes it feels like there isn’t so much to do in the game, but it has become a very good base to continue development on.