In order to setup Google Tag Manager tags for Rakuten, we'll need to have a Rakuten Merchant ID & Sitewide Tag
Rakuten will also supply you with a unique sitewide tracking code for your store that is unique to your account.
At the top right corner of your page, you'll see "MID 11111". This is your unique Merchant ID. This should be a 4 or 5-digit Merchant ID.
Updated about 1 month ago