Hello,
is there a way to query the login information (also password) of the customer with the API?I would like to check a customer in another system whether they are registered in Shopify.
you cannot get the password trough the api or any other way.
Through the Storefront API, you can get information about the logged-in customer --> https://shopify.dev/docs/storefront-api/reference/customers/customer. Although the password isn't available for various reasons.
