Shopify: why don't you have a public app?
While it is technically possible to add our 'app' as a public app, Shopify has the requirement that it's possible that a user of the app can immediately create an account to use. However, new accounts can only be created by ChannelEngine.
In the past, it was possible for users to create their own accounts, but this resulted in loads of (semi-)unused accounts and poor integrations. This is why only ChannelEngine can create accounts so the integrations can be properly guided and managed so both parties fully benefit. This practice, however, has the downside that we can't add Shopify as a public app.