Just being a finch doesn’t guarantee happiness. As Darwin observed in the Galapagos Islands, even these tiny birds had to evolve to adapt to their competitive landscape. The same evolutionary principles apply to Web APIs, according to speakers at the Web 2.0 Expo held in San Francisco on May 4.

Sam Ramji, vice president of strategy at API management software company Sonoa, put forth the comparison of Web APIs and Darwin’s finches. He said that APIs are evolving at a rapid pace, and adaptation is the key to success.

Ramji said that companies need to understand what developers want if they hope to evolve their APIs. He said that well-designed APIs with dedicated support will draw developers like finches to a feeder.

“In an API, [developers] want straightforward REST. They want nothing weird in the XML or JSON,” said Ramji. “They want totally standard security. They don’t want session-based authentication. Use HTTPS and use OAUTH. If you have to pick between writing documentation or writing sample code, get the sample code out there. Show me how it’s used in context and I can figure out the rest.”

Mashery, another API management company, administered a survey to 569 attendees at the Web and media-focused SXSW conference earlier this year. It found that developers prefer well-documented, simple APIs similar to those offered by Amazon, Google and Twitter. Delyn Simons, director of platform strategies and developer relations at Mashery, also said that most Web developers building with APIs aren’t doing it for business, but for pleasure.

When asked why they developed with APIs, “Two-thirds of the people who responded cited reasons other than ‘my employer pays me,’ ” said Simons.

Another big issue for developers in the Mashery survey was stability. Simons said that developers wanted APIs to remain static, as changes in behavior can quickly break applications built on APIs. She also said that developers were currently focused on mobile devices, perhaps because of the easy path to monetization there.

Ramji cited Apple’s iPhone App store as the model way to give developers incentive. “If you have a business model, let [developers] in on it. Don’t charge me to use your API. Look at me as the person spending my time building a cool application that will get you in touch with new users you never knew were there. If that’s valuable to you, give me some way to make money off of it,” he said.

Simons went on to say that even unexpected companies are now getting into the API market; Hallmark launched an API in April, and even The New York Times now has its own developer interfaces.

And that, said Ramji, puts developers between customers and businesses. Companies can engage with their customers in new and interesting ways using APIs, but such interactions won’t happen without care and support of those APIs.

“Show that you are listening by changing your API in response to the questions [developers] are asking,” said Ramji. “In your first attempt, you’re going to get the API wrong as a provider, guaranteed. You have to get it incrementally less wrong by listening to the developers in your community.”

What should be a concern is proper management of APIs. That’s an emerging space for ISVs, said James Governor, analyst at RedMonk.

“Ultimately, API management is going to be as important as the relational database management wave was,” he said. “If you think about the role of the DBA, all the performance issues had to be dealt with by the DBA; access to data structures had to be done by the DBA. I see this new role emerging in API management being equivalent to the DBA emerging.”