Other flaws in many APIs relate to security, simplicity, and scalability, says Dan Raju, CEO of cloud-based financial services vendor Tradier. Also, having only one version of an API is a good idea, says Chris Caselas, a developer at video syndicator RealGravity. Multiple versions of APIs can create issues such as incompatibility with the previous release, Caselas notes. "You should probably do it right the first time."
Poor API design usually keeps developers from using them, says Pamela Fox, a front-end engineer at online educator Khan Academy. But some poorly designed APIs -- such as Facebook's -- can't be avoided, she notes. Another example is the Google Maps API, which requires developers to sign up and use a key, to many coders' annoyance. "That just lowered the barrier for signup," prompting Google to eventually get rid of it, Fox recalls from her stint in Google's developer relations team.
PayPal's APIs had become complex and in some cases redundant, creating integration difficulties for developers. Then PayPal reworked its APIs to focus on JSON, REST and Oauth earlier this year, using a standard API model. "The new REST APIs offer all the same functionality in a simple, consistent way," says Deepak Nadig, PayPal's director of platform engineering.
APIs come from all sorts of industries
Mobile and cloud technologies are major drivers of the increasing number of APIs, as they let developers link customers to services residing on clouds and funneled to devices -- a reflection of the connected, heterogeneous reality of today's computing as compared to the old enterprise model of closed, complete systems. An Apple iPhone application, for example, might access an online merchant, PayPal payment services, and FedEx shipping services, Nadig says. As a result, "every company is feeling the mandate for them to expose APIs."
Participants in the burgeoning API landscape come from a variety of industries. Walgreen's, a $72 billion pharmacy chain, is counting on APIs in a big way in its e-commerce efforts: Its APIs lets both Walgreen's own app and others' applications order prescription refills, for example. As a result, those APIs are used to refill a prescription every second, says Joe Rago, a senior product manager for the Walgreen's API program.
Walgreen's also has an API for its QuickPrints photo-printing service, which gives third-party developers a 15 percent cut of net sales. Additionally, the company offers an appointment-scheduling API and its own software development kit.
Financial services provider Tradier has built its business by giving third-party developers APIs for cloud access to trade data, trade execution, and market access. Developers use them to build applications such as algorithmic and robotic trading systems.
Even the federal government has gotten into the act. Independent consultant Lane has been working on claims-processing APIs for the U.S. Department of Veterans Affairs. He's also worked with the Census Bureau and other federal agencies on API strategy.
This story, "The risks and rewards of the age of APIs," was originally published at InfoWorld.com. Follow the latest developments in software development at InfoWorld.com. For the latest developments in business technology news, follow InfoWorld.com on Twitter.