Application type 

The applicationType request attribute helps to answer the question: "Is this a frontend or backend request?". It is available in a frontend and backend context.

1

It is a frontend request.

2

It is a backend request.

Example:

$applicationType = $request->getAttribute('applicationType');
if ($applicationType === 1) {
    // We are in frontend context
} else {
    // We are in backend context
}