Google Merchant key and merchnat ID
Your Merchant Key is a unique code that helps to secure your communications with Google. Both you and Google will use this key to authenticate and verify the integrity of any messages that you exchange. You'll also need your key to integrate your off-the-shelf shopping cart or custom-built shopping cart with Google Checkout. Find your Merchant Key or Merchant ID by signing in to Google Checkout. Click the ‘Settings’ tab. Then, click on ‘Integration’. Your Merchant Key and Merchant ID will appear under the 'Account Information.'