Replying to the casual greeting "Hey, what's good?" depends heavily on the context of your relationship with the sender and your current mood. For a casual, friendly response, you can say something simple like "Not much, just chilling" or "Just getting through the workday, how about you?" If you want to steer the conversation toward something exciting happening in your life, you can share a brief update about a recent project, weekend plans, or a funny event, keeping the dialogue flowing naturally.