Should I use Azure Topics over Queues?

Question

I understand that Topics have the additional features of subscriptions and filters which Queues do not. In which case, when would I absolutely need to use a queue over a topic?

For consistency, could I use a topics everywhere including as a replacement for queues?

Answer 1

A topic is not a replacement for a queue. The combination of a topic and a subscription is. A topic is allowing to “replicate” the same message to multiple subscriptions. A subscription what actually holds messages. A subscription is identical to a queue in its attributes and behaviour. You could replace a queue with a topic+subscription combo if you’d like, generating 2 entities per use case instead of a single queue. Just keep in mind there’s a finite number of entities per namespace.