A Topic exchange is similar to a Direct exchange, but it supports multipart keys that contain multiple words separated by the “.” delimiter; for instance, a message producer can create messages with routing keys like usa.news, usa.weather, europe.news, and europe.weather. Binding keys 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.
A Topic exchange can use multi-part routing keys and bindings that include wildcards. A topic exchange sends a message to a queue if the message's routing key matches the binding key for the queue, using wildcard matching.