# Google Merchant Center setup for PopMCP

You end up pasting an OAuth Client ID and Client Secret from a Google Cloud project that has the Merchant API enabled and has been registered as a developer against your Merchant Center account.

- Auth: OAuth authorization
- Setup time: 12 min
- API base URL: https://merchantapi.googleapis.com
- Credentials screen: https://console.cloud.google.com/auth/clients
- Provider docs: https://developers.google.com/merchant/api

## Before you begin

- A Google Merchant Center account with products or a feed
- Admin access level in Merchant Center. Developer registration requires it
- A Google Cloud project where you are Owner or Editor
- The Google Account you sign in with must also be a user on the Merchant Center account

## Get your credentials

### 1. Enable the Merchant API on a dedicated Cloud project

Pick or create a project of your own, open APIs & Services -> Library, search for Merchant API, and click Enable. Enable `merchantapi.googleapis.com`, not the legacy Content API for Shopping.

Screen: https://console.cloud.google.com/apis/library/merchantapi.googleapis.com

### 2. Register the Cloud project as a developer on your Merchant Center account

Sign in with an Admin-level Merchant Center account and call `accounts.developerRegistration.registerGcp` for that account, passing the project you just enabled. Wait about five minutes before your first API call.

Screen: https://developers.google.com/merchant/api/guides/quickstart/registration

### 3. Fill in the branding and publish the app

Under Google Auth Platform -> Branding set the app name, logo, support email and your homepage, privacy policy and terms links. Then open Audience and click Publish app if Publishing status reads Testing.

Screen: https://console.cloud.google.com/auth/audience

### 4. Create a Web application OAuth client

Go to Google Auth Platform -> Clients, click Create client, choose Application type Web application, and name it `PopMCP`. Paste the exact callback URL from the PopMCP connect form under Authorized redirect URIs.

Screen: https://console.cloud.google.com/auth/clients

### 5. Copy the Client ID and Client Secret straight away

Copy both values out of the OAuth client created dialog into PopMCP's OAuth Client ID and OAuth Client Secret fields. If the dialog is gone, open the client and click Add secret.

## Fields PopMCP asks for

- OAuth Client ID (clientId) [required]: From your Google Cloud project → APIs & Services → Credentials → OAuth client. Enable the Merchant API on the same project.
- OAuth Client Secret (clientSecret) [required]: Stored encrypted; used server-side only and never shown again.

## Callback URL to register

https://app.popmcp.com/api/providers/google/callback

## Scopes requested

- https://www.googleapis.com/auth/content

## Verify

PopMCP opens Google's consent screen. Approve it and the connector flips to Connected with your Merchant Center account id shown. Ask the assistant to list a handful of products. Real titles coming back means the API is enabled, the scope is granted, and developer registration went through.

## Troubleshooting

### 401 "GCP project with id ... is not registered with the merchant account"

Cause: Developer registration was never run for this Cloud project. There is no Merchant Center UI for it, the registerGcp API call is the only way.

Fix: Run accounts.developerRegistration.registerGcp with an Admin Merchant Center login, then retry after about 5 minutes.

### Authentication errors when using an API key

Cause: Merchant API does not support API keys at all.

Fix: Use the OAuth client ID and secret. That is what PopMCP's two fields are for.

### Consent succeeds but no products are visible

Cause: The Google Account that signed in is not a user on the Merchant Center account, or is on a different sub-account.

Fix: Add that email on the Merchant Center Access and services page with at least Standard access, Admin for registration, then reconnect.

### Connection stops working after about a week

Cause: The OAuth app is still in Testing status, so the refresh token expires in 7 days.

Fix: Google Auth Platform -> Audience -> Publish app, then reconnect in PopMCP.

### 403 SERVICE_DISABLED for merchantapi.googleapis.com

Cause: The Merchant API is enabled on a different project than the one the OAuth client belongs to.

Fix: Confirm the project picker matches, then enable Merchant API in APIs & Services -> Library on that project.

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Source: https://www.docs.popmcp.com/docs/integrations/google-merchant-center/