Second, third-party software clients running on devices such as mobile phones, smart phones and tablets may connect to the DHIS2 Web API and read and write to relevant resources. For instance, third-party developers may create a client running on the Android operating system on mobile devices targeted at community health workers who needs to keep track of the people to visit, register vital data for each encounter and receive reminders of due dates for patient care while travelling freely in the community. Such a client application might interact with the patient and activity plan resources exposed by the DHIS2 Web API. The developer will not be dependent on deep insight in the DHIS2 internal implementation, rather just basic skills within HTTP/Web programming and a bit of knowledge of the DHIS2 data model. Understanding the DHIS2 data model is made easier by the navigable nature of the Web API.