Scenario 1: Simple Synchronous Operation @GET @Produces(MediaType.TEXT_PLAIN) public String greeting() { return "Hello!"; } Use Case: You have a straightforward operation that completes quickly and doesn’t involve any asynchronous tasks (database queries, network calls, etc.). Why No Uni: In this case, using Uni would introduce unnecessary complexity. You can simply return the result directly as a String. Scenario 2: Asynchronous Operation with a Single Result @GET @Produces(MediaType.APPLICATION_JSON) public Uni<MyData> getData() { return Uni.