RxJS is a library for reactive programming using Observables, which makes it easier to work with asynchronous data streams. It allows developers to compose and manage events, such as user inputs or data from APIs, in a more efficient and readable way. By using RxJS, you can handle multiple events and data sources seamlessly, improving the overall performance of applications. The core concept of RxJS revolves around Observables, which represent a collection of values over time. Developers can subscribe to these observables to receive updates and react to changes. This approach simplifies error handling and makes it easier to manage complex asynchronous operations in web applications.