A system comprising: an on-body drug delivery device comprising: a housing; a reservoir disposed within the housing; a delivery cannula having a proximal end in fluid communication with the reservoir and a distal end to be received within a patient; a drive disposed within the housing and configured to insert the distal end of the delivery cannula into the patient; one or more sensors configured to generate sensor data representative of at least one of a condition or an operational state of the on-body drug delivery device, the one or more sensors being mounted within the housing or on an exterior of the housing; and a first communication module coupled to the one or more sensors and configured to transmit the sensor data; and an external computing device comprising: a second communication module configured to receive the sensor data from the first communication module; a processor coupled to the second communication module; and a memory coupled to the processor, the memory storing non-transitory computer-readable instructions that, when executed by the processor, cause the processor to process the sensor data received from the on-body drug delivery device with or according to information stored in the memory of the external computing device to determine at least one of the condition or the operational state of the on-body drug delivery device. an on-body drug delivery device comprising: a housing; a reservoir disposed within the housing; a delivery cannula having a proximal end in fluid communication with the reservoir and a distal end to be received within a patient; a drive disposed within the housing and configured to insert the distal end of the delivery cannula into the patient; one or more sensors configured to generate sensor data representative of at least one of a condition or an operational state of the on-body drug delivery device, the one or more sensors being mounted within the housing or on an exterior of the housing; and a first communication module coupled to the one or more sensors and configured to transmit the sensor data; and a housing; a reservoir disposed within the housing; a delivery cannula having a proximal end in fluid communication with the reservoir and a distal end to be received within a patient; a drive disposed within the housing and configured to insert the distal end of the delivery cannula into the patient; one or more sensors configured to generate sensor data representative of at least one of a condition or an operational state of the on-body drug delivery device, the one or more sensors being mounted within the housing or on an exterior of the housing; and a first communication module coupled to the one or more sensors and configured to transmit the sensor data; and an external computing device comprising: a second communication module configured to receive the sensor data from the first communication module; a processor coupled to the second communication module; and a memory coupled to the processor, the memory storing non-transitory computer-readable instructions that, when executed by the processor, cause the processor to process the sensor data received from the on-body drug delivery device with or according to information stored in the memory of the external computing device to determine at least one of the condition or the operational state of the on-body drug delivery device. a second communication module configured to receive the sensor data from the first communication module; a processor coupled to the second communication module; and a memory coupled to the processor, the memory storing non-transitory computer-readable instructions that, when executed by the processor, cause the processor to process the sensor data received from the on-body drug delivery device with or according to information stored in the memory of the external computing device to determine at least one of the condition or the operational state of the on-body drug delivery device.