The present disclosure is directed towards systems and method for determining whether a scannable code displayed on a client device has been scanned. In particular, the systems and methods described herein involve activating one or more on-board sensors of the client device to capture output signals. Based on the output signals, the systems and methods include identifying discrete signals that indicate whether the scannable code has been scanned by a scanning device. Further, based on an analysis of the identified discrete signals, the systems and methods include determining whether the scannable code has been scanned by the scanning device.