For a mobile testing project, this is one of the most important stages and, in some cases, it is not considered as a separate stage but a part of the requirement analysis phase itself. A device matrix is generally required only when a high-level specification is provided at the start of the project about the type of application—native, hybrid, and web; the form factors—tablet, phones, and phablets; and the operating systems—Android, iOS, Windows, Tizen, Blackberry, and others are specified without providing the exact details regarding each of these. Regardless of the amount of details provided at the start of a project, it is imperative for a testing team to identify the exact devices and their operating systems' versions to provide optimum coverage during testing.

In this stage, the testing team can start the work of defining the spread of execution over various kinds of devices. Here, we recommend that you keep a few different categories of devices, such as: