Identifying electronic receipt data with a plug-in to a software application. Consumer purchases from merchants may be confirmed with an electronic receipt or message, which may be displayed by or transmitted to a consumer computer on which a software application such as a web browser and/or e-mail client application executes. A plug-in to the software application receives data of the software application that displays or stores transaction confirmation data generated by a merchant. The plug-in analyzes the software application data to identify potential electronic receipt data and notifies the consumer of the identified electronic receipt data. The plug-in provides for a choice whether identified electronic receipt data should be transmitted to a host computer that collects, stores and organizes electronic receipt data using a receipt program and receipt database.