Starting from Microsoft Dynamics NAV 2009, it was possible to publish page and codeunit objects as web services to allow external applications to access Microsoft Dynamics NAV or Microsoft Dynamics 365 Business Central data and business logic. In the later releases of Microsoft Dynamics NAV and Microsoft Dynamics 365 Business Central, it is also possible to publish Query objects as web services.
Page and codeunit objects can be accessed through the SOAP (short for Simple Object Access Protocol) web services. Queries can only be accessed through the OData (Open Data) web services protocol.