A Topic exchange is similar to a Direct exchange, but uses keys that contain multiple words separated by a “.” delimiter. A message producer might create messages with routing keys like usa.news, usa.weather, europe.news, and europe.weather.

Binding keys for a Topic exchanges can include wildcard characters: a “#” matches one or more words, a “*” matches a single word. Typical bindings use binding keys like #.news (all news items), usa.# (all items in the USA), or usa.weather (all USA weather items).

The exchange routes messages to the relevant queue or queues, depending on matches between the routing and binding keys.