Creating APIs is quite simple nowadays. You can have a functional API up and running in the Azure cloud within minutes. By using an OpenAPI library like Swagger to publish your API’s definition, other systems can easily integrate and utilize its functionality. The real challenge, as with many programming aspects, lies in maintaining the software once other parties start using your API. To help your customers integrate with your API, but also to have some influence over the way the API is called. A client can be created on the maintainer side and distributed using a NuGet package.