The Growth of Web Services

eBay published their first web API in 2000. It took another 8 years to get to 1,000 APIs on the web; it only took 18 months to get to the next 1,000 APIs.

ProgrammableWeb was founded in 2005, when they tallied 105 APIs. The current count is 2,016 and the rate of new APIs is doubling year over year.


What segments account for these APIs? Social networking sites are high on the list, followed by mapping, financial, reference and shopping. The single most popular API is Google Maps, used in 1,978 mashups.


Even more dramatic are the stats for how often APIs are called. Here's the Internet's new billionaire club:

74% of the APIs are REST and 15% are SOAP; the remainder includes JavaScript, XML-RPC and AtomPub. Over the past two years the use of REST APIs has increased as an overall percentage of net APIs, mostly at the expense of SOAP. Another trend is the increasing use of JSON; 45% of all new APIs support JSON. And on the authentication front, OAuth continues to pick up steam as over 80 APIs now have OAuth support.


The web is evolving from providing access to information, to providing access to services, to providing access to complex services -- also known as mashups. The popular and somewhat trivial example is the number of sites that call Google Maps API to show a map to their location. Links to Flickr, YouTube and Twitter are also popular. But what is the real business potential of these complex services?


APIs enable further leverage in systems development; that's why we can think of the web as a platform. Object-oriented software development is giving way to service oriented architecture (SOA) , which allows interfaces to be specified and their web services to be made available to any system with web access. This allows development organizations to focus on their core competencies, and leverage web services for the rest.


An example of how this is playing out is in monetizing the web. A new generation of web-based services has emerged, and many of these services are based on subscription revenue models rather than single transactions (aka shopping carts). Subscription billing is hard: while it's tempting for the many new developments in digital publishing, gaming, telecommunications, health care, consumer electronics and renewable energy to include a do-it-yourself billing system, there's no need to. Companies such as Zuora, Vindicia and Aria Systems  provide sophisticated billing systems through APIs, providing advanced functionality such as currency conversation, tax calculation, invoicing, fraud control, collections, reporting and analytics for a fraction of the time and expense that it would take to self-develop such capabilities. As we evolve towards a subscription economy with a variety of payment models, APIs providing web billing services will be leveraged to ensure secure, reliable billing.