Why API-First Design Isn’t Just for Startups

It’s easy to think that the notion of “ API first” should apply only to new companies, just designing their first product. But, with the growing API Economy, it’s come to be something all companies should consider. That was the objective for Kirsten Hunter, API Ninja at 3Scale, in her talk today at Gluecon. She’s been working with REST APIs for 10 years, including previous stints at LinkedIn and Netflix.
“Too often,” said Hunter, “REST APIs are created as an afterthought once the product has already been created as a tightly coupled system, with the frontend website and backend system entwined together in a highly codependent way and the REST API having to be ‘shoe-horned’ into this system as a separate entity.”
The problem with that approach is that the API then tends to lag far behind in terms of features, fixes, and testing infrastructure. “You must love your API,” she said. ”Make it first class. It must drive a meaningful experience with your consumers.”
A totally wrong mentality, said Hunter, is that of “every time an engineer comes up with a new approach, we should have a new API!” That will result in major Resource contention. Developers don’t like testing and Documentation, so this will just be another time-suck for them.
“The API First development mode forces consistency between interfaces – such as mobile vs. web. It makes you think about your use cases. It also allows for quick iteration.”
Why try this new model if you think. “We have our product, we won’t have another product?” Said Hunter: “Oh, yes, you will have another product!”  Don’t fall prey to such short-term thinking. Lay the groundwork.
Hunter went on to give examples of three API First companies: 1) LOB, a cloud printing provider, 2) Instagram, which opened up the API they had for mobile to expand to a web app, and 3) Etsy, which is now up to its Version 3. “Etsy learned its mobile and backend developers didn’t talk much, but now they do.” She said Etsy also found there was more confidence out there now about its API. “Developers know to trust it because the Etsy web site now depends on it!”
In response to an audience question about API versions, Kirsten noted that early versions of APIs never really go away — some people will just keep using them because they don’t want to change their code. “The key to get usage of your new version to make it so good that they will change their code to take advantage of the new goodies.”  She also noted in another answer that she doesn’t believe in SDKs — “they abstract your API” — echoing a previous presentation by John Sheehan of Runscope.
A great closing question directed at Kirsten was this one: “Is writing APIs a different skill than other developing?” To which she had this to say: “Developers like to write code. Use cases can be written by Front-end engineers or product managers.” But she also said she talks a lot in her evangelizing about the need to teach your developers to ask questions. 

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