As of today, most of the financial systems provides an XML-RPC API used for computer to computer communication and a GUI API used for human to computer communication. This represents an issue given the fact that in most cases the same services are provided by both APIs. This means that almost double amount of code is needed and when refactoring or applying some change, double amount of work is required. Furthermore, each one of the APIs themselves have some disadvantages. An investigation of the REST architectural style will be carried out to find out if it would be a proper solution for this issue. The investigation has the following goals: Understand the principles of REST. Get an understanding of what kind of data is handled by the financial systems. Devise a method to structure the access of the data using a REST API. Implement a RESTful API following that method. Show how the API can be used by persons and computers.