There are a number of things at work making this whole web API thing actually work. One of them that came up while I was at Google discussing APIs a couple weeks ago, while we were listening to Dan Ciruli (@danciruli) was the importance of being able to see an API request in the browser. It is something I think we often overlook when it comes to understanding why web APIs have reached such a wide audience.
I remember when I first realized I could change the URL in my Delicious account and get an XML listing of my bookmarks--this is when the API light first went on in my head. The web wasn't just for humans, it could be structured for use in other websites. Seeing the XML in the browser presented me links in a machine readable way, that triggered me to think about else I could with them, and which other systems I could put them to work in.
Being able to see the results of an API call in the browser helps stimulate the imagination when it comes to what is possible. This is similar to why API client tooling like Postman and Restlet Client are popular with developers--they help us see the possibilities. While not all APIs are simple enough to allow for viewing in the browser, when at all possible, we should keep things this easy, because you never know when it will make a mark, and help folks better understand what is going on under the hood, allowing them to put our APIs to work in ways we never expected.
