These costs definitely seem high. As a reference point - to get through the Salesforce AppExchange security review process, believe the cost is $2,700. It’s an extremely rigorous security testing as one might imagine with corporate CRM data.

Is that ran by SalesForce? If so, could they be subsidising it?

Yes AppExchange is run by Salesforce and they likely do subsidize the security review. They also take a percentage of revenues from direct AppExchange installs(believe 15-25%) after listing. SF wants third party devs building out functionality and the ecosystem. Google seems to be taking a different approach...

Seems like a business opportunity for somebody to create a compliant API that allows other people to write software that accesses gmail data in a limited fashion.

I'd say that this is nearly impossible.

We talk about two different data sets here: * The actual User data. * Data from third persons, including, but not limited to their e-mail address.

While a user can agree that their own data should be processed by a third party, the problem is that he cannot consent for other people.

And in my understanding (INAL), every part of the software where those third person information is transferred or processed needs to be part of that full assessment.

A limited API that does not give out any third persons data would have to somehow filter out all the information of all third partys.

Their TOS explicitly forbids doing that.