I am slowly working my way through hundreds of APIs and doing business reviews of their approach to delivering their APIs.
At API Evangelist I'm focused on the business of APIs, with a minor focus on the technology behind those APIs. So when I publish a business review of an API, I will add it to my API database, then move on.
That is, unless I identify a story -- an innovative approach, monetization strategy, or anything that I feel needs to be talked about in more detail.
While reviewing the Freshbooks API I found three notable building blocks:
Application Billing - A built in billing and payment framework for Freshbook applications and beyond
Webhooks - Framework for enabling application callbacks, URLs where the Freshbook system can send notifications to third party applications
FreshBooks Add-on Store - Application store and development platform for developers to build custom apps, showcase, and sell to Freshbook customers.
Self-Service Application Frameworks like the Freshbooks Add-On Store are growing more common. I've talked about similar systems from Box.net and Google Apps Marketplace. The Freshbooks Add-On store is not 100% self-service, but it is close.
Webhooks are nothing new, but Freshbook offers a standardized approach to deploying web-hooks that makes them easy for developer to use.
A built in payment system is definitely a notable API building block. Providing developers with a baked-in payment system for handling application monetization is very innovative.
Where do these three building blocks fit into the big picture? I try to build profiles for common API building blocks, I don't have profiles for self-service application frameworks, webhooks, and payment systems, but as I evaluate more I will define these as more innovative building blocks for API owners to use.
I will definitely be keeping an eye on the Freshbook approach to their API.