However, developing these applications is far from trivial because of the engineering challenges—ranging from subscribing to various data sources, defining complex streaming transformations, to integrating with multiple data sinks. 

To address the complexities of building these applications, a declarative interface offers a robust solution. A declarative approach, where developers specify what to achieve rather than how, simplifies the development process by making code more modular, reusable, and understandable across different teams. It also enhances system maintainability and debuggability. 

We pioneered a declarative interface rooted in GraphQL at Airbnb to significantly ease and standardize the development of streaming applications. This methodology has been embraced by over 20 teams within Airbnb for them to more easily develop, maintain, and scale streaming applications, staying ahead in the fast-paced world of real-time data.