I know this is an old post, but maybe it can still be usefull to someone. To start the standalone you need to pass both the worker config (connect-standalone.properties) and the connectors configurations (mongo_connector_config.properties in Robin's case). For someone with the same problem, bare in mind that for starting the standalone connector you need to pass ".properties" files. To update or add new connectors you would need to pass ".json" files. You can see in the confluent documentation page here. bin/connect-standalone worker.properties connector1.properties [connector2.properties connector3.properties ...] Vicente ... View more