You can connect a Shopify store over OAuth and import its products, customers and collections into Litestore.
Litestore sends each new newsletter signup from the storefront to a Klaviyo list.
Litestore sends each new newsletter signup from the storefront to a Mailchimp list.
Litestore sends each new newsletter signup from the storefront to a ConvertKit form.
The guide explains every value you set and what Litestore does with it.