Bridges are essentially a way for one MQTT broker to connect to another MQTT broker. This is a very useful feature and enables you to setup your own HA "cluster".
You can create your own bridge from the console page.
In the "Connection uri" field you must enter a connection string in this format:
If you don't enter a port the default 1883 will be used.
In the "Direction" dropdown you can choose between:
With the 'Both' option you can create loops. This means that the brokers are forever forwarding each other the same message.
To get around the loop problem you can specify a "Local prefix" and a "Remote prefix". Local in this context means the broker where the bridge is defined. This means that only a topic that matches the prefix will be forwarded.
We have two brokers, A and B, where A is the local broker hosted by CloudMQTT.
On the console page we enter the connection options to broker B and select the direction "both". We then enter "B/" into the "Local prefix" field. We enter "A/" into the "Remote prefix" field.
Then we publish the current time to the topic "A/time" on broker B. On broker A you can subscribe to "B/time" and you will see the times published to broker B. This works in both directions.