In this tutorial, we learn how to build a minimal Ably SDK using NodeJS. We start by setting up the project and installing its dependencies. Then, we create an Ably class capable of connecting to Ably via a WebSocket connection. Next, we implement methods for attaching to channels, detaching from channels, publishing messages on a channel, entering presence, and leaving presence on a channel. Finally, we discuss why using an Ably SDK is preferable over building one's own solution in production environments.