In today’s computer environments the systems are getting bigger and more complex for each day that passes by. The motivating factor for this is that the customer wants to achieve more and more with their computer systems than before. The only way to really solve this task is to use even more APIs (Application program interfaces) in their systems.     When using more APIs in a system, there is a chance that the specific system provides the same type of API twice, which of course, is a waste of storage and resources. In addition, the more APIs a system contains, the bigger the risk is for mismanagement of these APIs. In the worst case, this can result in security breaches or data leaks.  This thesis investigates specific APIs provided for a customer of Sigma IT Consulting. The aim is to evaluate and organize the APIs according to their usability criteria. The main focus of the evaluation is the available documentation which will be evaluated by a questionnaire survey distributed to senior software developers at Sigma IT Consulting in Växjö. Conclusions will then be drawn depending on the result from the survey, and we can then see if Azure API management (which is a service to make a system more user – friendly) is accurate in its way of organizing with the API usability as the main focus! Unfortunately, Azure API management did not have any possibility what so ever to customize the API placement in a system, and the only way the APIs are organized is in alphabetical order. Therefore, a prototype with even more sorting functionality than Azure API management will also be presented in this thesis.