The usage of the Internet is growing constantly in the whole world, also in Finland. Electronic invoicing is a fast-increasing area in the business world. One of the most widely used electronic invoice format in Finland is TietoEnator’s own TEAPPSXML standard, which is a free, XML-based format.

Energiakolmio Oy is using this standard to handle these invoices. Correct and smooth processing of these invoices is essential. Few companies offer value added services for both parties of a transaction; however, one of these companies is the above Energiakolmio Oy. For handling these documents efficiently, the key elements of these invoices must be fast-accessible; they must also support the connection with the company’s own information system.

The thesis presents two aspects of archived invoices: one is the archiving of the invoices processed by the employees of this company; the other is a reporting system which is offered for the customers to get up-to-date information about their invoices.

The projects were created in .NET Framework 2.0 using Visual Studio .NET 2005. The programming language was C#, the database server was MS SQL 2000. In addition to the mentioned technologies, it also used XSLT technology.

The archiving component is in production for few weeks, the feedbacks are positive. The reporting service is waiting for the final approve.