Open APIs context. An open API is a piece of software that allows the owner of a network-accessible service to give universal access to consumers of that service, such as developers. An API is a software intermediary that makes it possible for application programs to interact with each other and share data. Through the consistent use of open interfaces, the exchange of information and results of different actions and among different partners involved, is possible in an easy and useful manner, e.g. an application built on top of Dresden’s Urban Platform should work also – at technical level – with Valencia’s or Antalya’s Urban Platform. Of course, it needs to be taken into consideration that the service is developed with certain requirements of data availability and, if they are not complied, the application will not work properly, but at least it will be deployable. Additionally, this interoperability at API level provides the opportunity to 3rd parties to develop on high-level services that should work on multiple platforms. In this way, 3rd parties can easily adapt their software assets to new platforms and gain a larger visibility. Furthermore, the APIs exposed to Data Publishers to provide data and to the Data Consumers to query and retrieve data (API-Level Interoperability) should be fully documented and the documentation should be freely accessible as opposed to a proprietary API where the access to which is bound to commercial and non-disclosure agreements.
