The Call API is a management front-end for OpenSIPS 3.1+ SIP servers, aiming to abstract the SIP layer and to simplify the management of more advanced SIP call flows. Moreover, it enables event-driven architectures by providing real-time events on the handled call scenarios. The OpenSIPS 3.1 major release is not just about one piece of software, rather an entire ecosystem! After the recently introduced opensips-cli console environment, aimed at improving the interaction with an OpenSIPS 3.0+ server, we are proud to introduce the Call API -- a responsive, fully asynchronous, high-throughput API, built to abstract all the complexity behind the more arcane SIP calling scenarios (think click-to-dial scenarios, blind transfers, attended transfers, etc.) into intuitive, easy-to-invoke JSON-RPC commands. The first half of the presentation will include an architectural overview of the API. You will learn how to interact with it, how the API further interacts with the OpenSIPS backend, as well as some best practices on writing API clients in your favourite programming language. In the second half, you will learn about the specific SIP scenarios exposed by the API, how they work behind the curtains and what kind of services you can build on top of them.