# Subscribing to an MQTT topic

1. Open Node-RED.
2. Add an mqtt node from the input category to the workspace.
3. Double-click the mqtt node to open the Edit node dialogue.
4. In the drop-down list Server, select a server to connect to or add a new MQTT broker.
5. In the text box Topic, enter the topic you want the node to subscribe to.

6. ## NOTICE

   Use / as hierarchy separator. You can use MQTT wildcards: + for one level, # for multiple levels.

7. In the drop-down list QoS, select the Quality of Service level.

8. ## NOTICE

   0 (fire and forget): Arrival of the message solely relies on the underlying Internet Protocol network. Message loss may occur.

   1 (at least once): The message is assured to arrive, but may arrive more than once.

   2 (once and once only): The message is assured to arrive once and only once.

9. Click Done to apply your changes.
10. Add more nodes to the workspace and connect them to a flow with the mqtt node being the first node.

1. Once you deploy the flow, the mqtt node injects messages of the selected topic into the flow.