We'll, there definitely are distinct classes of journalists that have special privileges. These classes are not defined by law but are implemented and supported by institutions (such as when special access is granted to events or killings generate international attention).

There is no such thing as a "licensed journalist" because such licensing has been historically used to limit freedom of the press. However, there is an implicit understanding of what constitutes being a journalist that is similar and it is displayed when Judges choose whether or not to force a journalist to reveal their sources.

The core idea is that intent matters. Building such an app to create public discourse by someone with a clear history of journalistic actions is likely to face different regulatory penalties than an individual with no such history who builds such an app for entertainment or profit.

Edit: There is argument to be made that this "soft licensing" serves to extert control over journalists.