what is an API ?

I met a friend after a couple of years and we started talking about our work. We started talking about API Infrastructure and midway thru the discussion he asked me a very simple question. what is an API and how is it different from a Service , Why is a service Bus infrastructure different from a API Infrastructure. At that moment I realized that this is question that i should have answered first and here i am writing it down.

api definition:
- An api is reusable asset which can be invoked on the web. As a reusable asset the api can be combined/invoked from another website/mashup/application to add value for e.g. retrieving the List of Movies I have watched on Netflix over the last week and displaying it in my website.

what is the difference between a Service Infrastructure and API Infrastructure

I sometimes use services and apis in the same context and there is no difference between the two in my mind however architecturally there are two types of services

a) services which i create within my application/enterprise for business process reuse and loose coupling between the various technology stacks available. This is the soa story and i am not going there. there are enough products out there which can solve the problem

b) service or APIs which i create so that they can be consumed by my partners /consumers or even shared across departments and services which i consume from other guys.

From a technology perspective "a" requires "Service Infrastructure" while "b" is the "API Infrastructure"

• "Service Infrastructure" is about integration of services while "API Infrastructure" is about producing and consuming apis/services.
• "Service Infrastructure" is part of the middleware technology while "API Infrastructure" is more of a gateway functionality. In "Service Infrastructure" i am trying to integrate across disparate technologies how to integrate with ftp/email/jms etc while "API Infrastructure" is about exposing apis via http as POX/REST/SOAP
• the concerns of "API Infrastructure" are security,scale, sla& monitoring,visibility instead of transport mediation/data mediation/process orchestration. If i am 1800Flowers.com and exposing an api to buy flowers then i would be concerned of making it available on the web with regards to scalability and security (for e.g. how can i guard myself against XML xDos/MDos Attacks) on the other hand if i were an enterprise doing service integration i would looking at how can i expose my Messaging (JMS) backend with a HTTP front end and do not end up having duplicate messages , architecturally an API Infrastructure sits in front of the Service Infrastructure.
  

Adoption of Enterprise 2.0/N.0 == More API Traffic
-------------------------------------------------------------

Enterprise 2.0 as an idea was floated as an idea late as 2007 and my interest in Enterprise 2.0/N.0 stems only from the product engineering perspective and the new infrastructual requirements it poses.

What is my version of Enterprise 2.0 ( i can see you guys rolling your eyes but give me a hearing first...)

For me the definition of "Enterprise 2.0 is the successful adaption of social software platforms within companies, or between companies and their partners or customers". I have to say "successful adaption" because i do not think the enterprise will adapt the web 20 completely, Enterprises will never give up the control but they would like to adapt the practices of web 20 with regards to collaboration & self service and agility and adapt them into the enterprise.

How will they get manifested within the Enterprise:

I would like to see "Boeing" build its next generation "Partner Management/Tracking Platform" using mashups and social software paradigms , the idea of having the "part tracking" portlet implemented as a mashup and exposed as a widget of choice on someone's iphone, blackberry which is very salivating thought.

With Google announcing SDC and vendors providing support means only one thing i.e. we are going to see more api traffic coming from the enterprise and thats a very good thing.


End Result
more APIs /more enterprise data getting exposed/ more traffic.... how are you going to manage this ?