Dart is a single-threaded programming language, that is, all of the application code runs in the same thread. Put simply, this means that any code may block thread execution by performing long-time running operations such as I/O or http requests.

Although Dart is single-threaded, it can perform asynchronous operations through the use of Futures. Additionally, to represent the result of those asynchronous operations, Dart uses the Future object combined with the async and await keywords. Let's understand these important concepts to develop a responsive application.