Smartphone-Cloud Architecture

The Smartphone Component of the App connects to the Cloud Component

The following diagram illustrates this architecture. Unlike most uses of this architecture, COVID-19 Apps often provide Peer Communication between smartphones running the same App (e.g. using Bluetooth for contact tracking purposes).

Smartphone-cloud architecture diagram



  • can be cheaper to operate as data storage does not need to centralized;
  • can provide more user privacy if user data is kept on the smartphone;
  • all smartphone capabilities provided by the smartphone operating system are available for use (e.g. for Peer Communication);
  • implementation technologies, and developers with appropriate skills are widely available.


  • more code needs to be written and tested; development is more expensive;
  • more skill sets required on the development team;
  • additional components and communication channels need to be defended.