Master’s Thesis follows the development of the Web application which allows monitoring and administration of SQL Server instances which are used for working with SQL Server databases. It also describes theoretical and practical roles of the implemented application and all similar applications which include some of the functionalities implemented in this application. Additionally, all relevant functionalities present in SQL Server, that are either implemented either in the very similar way or to be better, are also described. D3.JS library, which is necessary for the visualization of input data, is also described. The developed application allows login and registration with basic monitoring and administration features. The user can use some of the implemented features like checking the basic instance information which is mostly system-specific like CPU or IO usage or checking the state of currently active sessions. Other available major features are viewing of SQL Server Agent-like view which allows checking of the list of SQL Jobs and details for the chosen job, using of own dashboards which allow checking of multiple instances on one view and defining of triggers which show notifications to the user in case one of the conditions is true. The web application is implemented with SQL Server database, N-tier architecture and ASP.NET Core framework with MVC (Model-View-Controller) software architectural pattern. The whole application is separated into several smaller applications where the correct functionality of each part is ensured with JavaScript libraries React.js and Redux. They are mainly used for responsive applications which are fast, simple, scalable with easy data manipulation. Backend part of each part of the application is implemented with SQL Server instances and databases and communication is possible via business logic layer, data access layer and Dapper which allow using of T-SQL queries and stored procedures.