Service Bus queues vs topics and subscriptions; Basic tier has no topics

Azure Service Bus is a fully managed enterprise message broker. Applications send messages to it and other applications receive them later, which decouples senders from receivers: the receiver can be offline, slow or scaled differently, and the message waits safely. Service Bus is built for high-value messages, such as orders or payments, where each message must be processed reliably. You work with it in Python through the azure-servicebus package.