In this talk, I will describe how to build an event-driven serverless backend using Firebase services and Cloud Functions and show examples, of course. Did you know, for example, that last year a new version of Cloud Functions, v2.0, was released, which now operates fundamentally differently, opening up many new opportunities? Or that a cloud function can be written not only in JS and TS but also in Python or Java, and that you can create your own event that will trigger the function? Or that you can connect any Firebase service, or any Cloud API, for example, Genkti, or an external API, such as ChatGPT? That eventually, you can create your own function in a language not natively supported out of the box, like Dart or Rust. Let's figure it out together, how it works!