How to install DC Merchant Centre Plugin

This documentation supports V1.0 and V1.1

Setting up accounts

Google Developer Console

The Google Developer Console is used to create an OAuth key to securely link your website and your Google Merchant Centre together, allowing your website to submit data to your Merchant Centre.

Follow the steps with the images below:

Navigate to and sign up with an account. You will be greeted with a dashboard type page

You will need to create a new project. Click on select project.

In the top right corner select the '+' to create a new project

Give it a name - preferably the name of your website. Then Click Create

Now click on Credentials on the far left side of the webpage.

You will then be greeted with a popup box asking you to create some credentials.

Click the box and select OAuth client ID.

You will then need to click the 'Configure consent screen' button.

You will be taken to the OAuth consent screen. Here you will enter a name and click save.

You'll then be taken back to the Credentials screen, Under Application type select Web application. Give it a name and look at the authorized redirect URIs input field. You will need to add the following http(s)://{{}}/DCGoogleShoppingContentApi/AuthCallback Click create Your OAuth client id and client secret will now be generated. Keep hold of both of these as you will need them when setting up the plugin.

Next, navigate to the library

You need to activate the Content API for Shopping. Start by searching for shopping in the search box.

Click on the api and then click enable. That's it for Google Developer Console.

Google Merchant Center

These steps only need to be followed if you haven't yet created a Google Merchant Account.

Navigate to

Sign in with the same account that you used to sign up to the developer account.

Follow the steps on the images below

Navigate to Settings > General on the right hand side. You need to fill in your details including your website address - making sure that your web address is prefixed with http:// or https://. Click save at the bottom of the screen.

You will then be asked to verify that you own the website

Follow the steps through to verify that you own the website.

Once you have verified, your settings page should look something like this

To claim your website you need to edit the settings again and enable 'I want to claim this website'.

Your page should now look like this

Installing the DC Merchant Centre Plugin

Upload the plugin to the /plugins folder in your nopCommerce directory.

Restart your application (or click 'Reload list of plugins' button).

Scroll down through the list of plugins to find the newly installed plugin.

Click on the 'Install' link to install the plugin.

Note: If you're running nopCommerce in medium trust, then it's recommended to clear your \Plugins\bin\ directory


Configuring the DC Merchant Centre Plugin

Firstly you will need to do some code changes in the Web.Config. Only a small change.

You only need to do this change for nopCommerce versions 3.6 and below

In the Web.Config find where the dependant assemblies are written.

There will be an assembly called Newtonsoft.Json.

Replace that with the following code:

   <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
   <bindingRedirect oldVersion="" newVersion="" />

Save the file.

Our plugin requires a higher version of Newtonsoft.Json but nopCommerce, 3.6 and below, uses v6. This peice of code gives us v6 but fakes it as being v7, allowing our plugin to run.

Go to the backend of the website and navigate to the plugins list.

Click the configure button on the plugin.

Follow the steps on the images below

You will come to the configuration page. Your Merchant ID is the number you got from Google Merchant. Client ID is the ID you received from Google Developer Console. Client Secret is the ID you also got from Google Developer Console. Fill these in and click the request access button.

Click allow

You will then have an Access Token and Refresh token showing in the configuration page.

The product prefix input is used for when you have multiple shops going to one merchant center. The product prefix will prefix a character to the product id before it is uploaded to the merchant center. You can use whatever prefix you like here to distinguish products between sites.

How to use the DC Merchant Centre Plugin


Configuring the Category level is reccomended to enable the Merchant Center to categorize your products.

Categories for a product can be set at a category level as well as product level.

To set a category at category level, navigate to Catalog > Categories > List and select a category.

Then navigate to the Google Shopping Category tab.

Here you can set the category of the product categories.


Categories can also be set on products. This will overwrite its parent category for this product.

To set a category at product level, navigate to Catalog > Products > Manage Products and edit a product.

Then navigate to the Google Shopping Category tab.

Here you can set the category of the product.

Required Fields

For a product to successfully upload to Google Merchant Center, you need the following fields to be set per product:

  • Title
  • Description
  • Price
  • GTIN
  • MPN

You may run into issues if any of these are not set, you can view the system log to find out which fields are missing from a product.

Scheduled Task

A scheduled task will run every 5 minutes that will upload any products that have changed to the google merchant center.

It will also check to see if any products have been changed since it last uploaded and reupload them if they have changed.

The Scheduled Task will also upload products that have not changed in 20 days to prevent Google from removing valid products from the Merchant Center.

Google Merchant Center

When using the Google Merchant Center shipping charges should be defined in Google Merchant Center. This is so that Google can compare shipping prices between products.

Follow the steps on the images below

Shipping settings are country specific, so there needs to be shipping settings for each country you ship to.

As the products are sent to Google Merchant Center they will be assessed to see if they comply to Googles Standards. It will tell you what the product fails on if it does fail. Like so:

Google will also tell you what it did receive. If your products comply with the Google Standards they will be accepted and begin to be shown on Google shopping.


Common Error Messages

This error message is usually due to non-matching URL's, The website url must be the same as what you set in the Merchant Center


You can read more here :

This error is shown when shipping settings are not set in the Merchant Center.

They can be set here :

You can read more here :

This error usually happens when the country you are shipping to does not have any shipping settings in the Merchant Center

You can read more here :

This error usually happens when the currency that is submitted isn't the same as what is on your website.

You can read more here :

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