How to create a custom app and obtain Shopify keys
To connect your Shopify store and your RSS Ground account you need to create a custom Shopify app (previously called 'private app').
Log in to your Shopify store.
In the left sidebar of the admin area find the Apps section.
To create or edit your Shopify app click the Develop apps option.
If you already have an app, click on the app's name to get the keys.
If you don't have an app yet, you need to create one. Press the Create an app button in the upper right corner.
Name your app and on the next step press the Configure Storefront API scopes:
If you already have a custom app, go to the Configuration section. Find the Storefront API configuration and press Edit.
Here you grant your app permissions. You need to allow reading content and product listings:
Save this configuration.
Now press the Install app button in the upper right corner.
As soon as the app is installed, in the API credentials section, you will find the Storefront API access token:
You will use this token in the Shopify Feeds generator in RSS Ground.
Press the Authenticate button and enter your Shopify store domain name (without https://), then specify your Storefront API access token.
If you are still using the legacy private Shopify app, click the "Use private app credentials" option and specify your API key and Password.
And don't forget, you can use the Default settings option to save your credentials, to automatically enter them every time you generate a new Shopify feed: