|REST ||Uses the API key, which is generated when you create the source, to ingest data.|
|MQTT||Subscribes to an MQTT broker.
- MQTT involves a central broker with messages organized by topics. Listener can subscribe to one or more topics on a broker, and write messages to the firehose. From the firehose, Listener routes streams to the designated target.
- Messages within MQTT have an associated QoS (Quality of Service) level, which determines the broker's level of effort to ensure a message is received. Listener supports messages with QoS level 0 (send at most once) or QoS level 1 (send at least once).
- For QoS level 0, Listener writes the record to the firehose. The broker assumes Listener handles the record as soon as it is sent.
- For QoS level 1, Listener waits until a message is written to the firehose before acknowledging success to the broker.