If you want to be technically correct, you can make all your apps exclusively in Swift too. The fact is most large projects are already using both. The trend for new code is to be written in Swift.<p>At the very least, your need to be able to reason about both languages. Refusing to learn one of them is a disservice to yourself as an iOS dev IMO. Denying that would be silly. If you haven&#x27;t taken a look at Swift, there is no better time than now to start.