Types of APIs
We see two types of APIs: private and public. No matter what you may hear in the
media, private APIs are the more prevalent variety. You know about the Facebooks and
Twitters of the world and their use of APIs. What you probably don’t know is that
those same companies are likely making much more extensive use of their own APIs
to drive their websites, mobile apps, and other customer-facing products. In our ex-
perience, visible public APIs like these are just the tip of the iceberg. Like the large
underwater mass of an iceberg, most APIs are private and imperceptible, internal to
companies, used by staff and by partners with contractual agreements. This use of APIs
is what is really driving the API revolution. Do not limit your thinking about the ways
APIs can be used to public examples like the App Store. Partner and internal use of
APIs is often more valuable.
Much of the discussion of APIs assumes that they must be open to the public to be of
value. This is not the case. We believe that private APIs are having a transformational
impact on most companies, in many cases much more so than public APIs.
The New York Times API started as a private API and is transforming their business.
“The NYT API grew out of a need to make our own internal content management
system more accessible so that we could get the most from our content,” said Derek
Willis, Newsroom Developer at the Times. “The API offered a way to give more people
access to create more interesting pieces. We are the biggest users of our own API, and
that’s not by accident. The API helps our business in other ways: creating brand aware-
ness and helping us attract talent. But fundamentally, it helps us do our own jobs
better.”
To further frame this discussion, let’s clarify what we mean by public and private. Public
means that the API is available to almost anyone with little or no contractual arrange-
ment (beyond agreement to the terms of use) with the API provider. Private APIs are
used in a variety of ways, whether to support internal API efforts or a partner’s use of
the API. API providers also offer private APIs to large customers with appropriate legal
contracts. Private and public really refers to the formality of the business arrangement.
It doesn’t refer to the API content nor does it refer to the applications developed using
the API.
Finally, public and private APIs are, in the end, still APIs. Often a company will start
with a private API and eventually open some or all of it for public access, possibly with
additional restrictions. Other times, a company will launch a public API, then realize
how important it is for internal development and in the end it is private use, not public
use, that provides the real business benefit.
AccuWeather, for example, is well known for providing weather data to the general
public, which would lead most to believe that their APIs are public. But remember: the
private/public distinction refers to the arrangement with partners, not to the availability
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