The Diamond plan is meant for users with more complex needs, web designers being the best example.
This plan provides all the features that come with the Platinum plan (such as integrations with 3rd Party Apps and payment gateways, SSL encryption, domain aliasing) and, still like the Platinum plan, has no limitations. In addition, it allows for creating 2 subaccounts (3 with your master account) and offers a complete white label forms solution.
Learn more about subusers and subaccounts.
Learn more about white label forms and see how you can provide your clients with a form management tool branded with your own identity.
You can find all the Diamond plan features listed and described in our Features Matrix.