Sage API Restrictions and Sign up for the new member

SUGGESTED

Hi All,

It's my first time here, a little intro, I'm basically a c# developer working with various mobile/server apps to bring joy to clients.

As it's my first dealing with Sage, I just want to confirm a few things from the community regarding Sage 50cloud Accounting API for third party app access:

1. As far as the API is concerned, there's no difference with accessing Sage 50 with different subscriptions (Essential, Standard and Professional), as long as the feature being accessed is available (such as "Create sales and purchase orders" can only be done on the Professional version), correct?

2. Registering for private Third-Party App access is free but API access must be authorized by the client (company subscribed to Sage 50 cloud)?  Private in terms of the third-party app being made only available to one client and not distributed or being part of the app marketplace, correct?

3. The Sage 50cloud Accounting API is limited to all functions listed here:  https://developer.sage.com/api/accounting/api/

4. Signing up as an app developer grants a free developer license for API development and testing located on the client Sage account, correct?

I'm hoping all the above 4 points are indeed correct.

Thank you for your guidance.

Makoto