Barcode OI Plugin is a free Android extension for the OI Shopping List app developed by OpenIntents. It allows users to add or check items in their shopping list by scanning barcodes. However, users need to have the ZXing Barcode Scanner installed on their device to use this plugin.

Currently, the plugin only supports US UPC barcodes, which are resolved automatically. For European EAN products, users have to enter them manually. However, the plugin remembers the entered products, which saves time for future shopping lists. Overall, Barcode OI Plugin is a convenient extension for OI Shopping List users who want to save time while grocery shopping.