Scan Add-On/Extension Codes#


Add-on codes are only supported in BarcodeCapture.

The Scandit Data Capture SDK supports add-on codes (also known as Extension Codes) for EAN-8, EAN-13, UPC-A and UPC-E codes. These codes encode additional product data like an issue number, date or price. There is a two and a five digit version. This guide will show you how to enable and read out add-on codes.

../_images/ean13_with_addon2.png ../_images/ean13_with_addon5.png

Before you start…

To get the most out of this guide, we recommend that you have read the following articles:

Enabling Add-On Codes#

Add-ons are handled through symbology extensions. To scan add-on codes:

  • Enable the main symbologies that should be scanned (EAN-8, EAN-13, UPC-A and UPC-E).

  • For each main symbology enable the wanted add-on symbology extension(s). The two add-on extensions are:

    • two_digit_add_on

    • five_digit_add_on

The following lines of code show you how this is done to enable the two digit add-on for EAN-13, UPC-A and the five digit add-on for EAN-8 while UPC-E is not expecting any add-ons:

var settings = BarcodeCaptureSettings();;

var ean13upcaSettings = settings.settingsForSymbology(Symbology.ean13Upca)
  ..isEnabled = true
  ..setExtensionEnabled("two_digit_add_on", enabled: true);

var ean8Settings = settings.settingsForSymbology(Symbology.ean8)
  ..isEnabled = true
  ..setExtensionEnabled("two_digit_add_on", enabled: true);

settings.enableSymbology(Symbology.upce, true)


Enabling add-on codes will slow down the recognition of non-add-on codes slightly because the Scandit Data Capture SDK needs to make absolutely sure that no add-on code was missed. If you are not expecting add-on codes for a certain symbology then don’t enable them.

Reading Add-On Code Data#

When add-on codes are enabled the Scandit Data Capture SDK automatically couples the add-ons to the main code and returns the add-on’s data through Barcode.addOnData. There are two potential cases when a barcode of a symbology with enabled add-on extension is returned:

  • The barcode has an add-on and is returned with add-on data

  • The barcode does not have an add-on and is returned without add-on data

Inside BarcodeCaptureListener.didScan() the data can be retrieved from the recognized barcode as follows:

var barcode = session.newlyRecognizedBarcodes.first;

var data =;
var addOnData = barcode.addOnData;
if (addOnData.isNotEmpty) {
    // Do something with the data & addOnData.
} else {
    // Do something with just the data.

Avoiding the Scanning of Barcodes without Add-On#

For a use-case where only barcodes with add-ons should be scanned, the same type of rejection as shown in the Barcode Capture Reject Sample can be used.

If add-on data is available:

  • Manually emit feedback

  • Change the overlay’s brush to the default

If no add-on data is available:

  • Don’t emit any feedback

  • Change the overlay’s brush to transparent