scope:

The preliminary API work in the present document was completed in April 2018 and the final NGSI-LD API is now instead standardized in ETSI GS CIM 009 [20].

The purpose of the present document is the (preliminary) definition of a standard API for Context Information Management (NGSI-LD API) enabling close to real-time access to information coming from many different sources (not only IoT data sources). The present document defines how such an API enables applications to perform updates on context, register context providers which can be queried to get updates on context, query information on current and historic context information and subscribe to receive notifications of context changes. The criteria for choice of the API characteristics are based on results in the Use Cases [i.1]. The present document is labelled "preliminary" because it will be published widely in order to elicit comment and critique from the user communities and their comments will be used to modify and improve the later final API specification.