Techniques for disparate barcode transaction processing are provided. A first barcode associated with a first service is presented at a self-service device, which is associated with processing a second barcode for a second service; the first barcode is disparate from the second barcode. The self-service device identifies the second barcode as a foreign barcode and consults an external service. The external service identifies a next transaction of an itinerary for a customer associated with the second barcode and communicates that to the self-service device. The self-service device completes the next transaction on behalf of the customer.