Many businesses are realizing the opportunities that come when services, products, data and delivery channels are managed via APIs.As a result, businesses are exploring API strategies that commence with an API-first design approach and recognize the importance of providing a high-quality developer experience through the creation of resources such as detailed documentation; sandbox environments to test API calls; and SDK and code snippets.But after these are all in place, then what? How do businesses scale up the use of their APIs to build out a commercially viable ecosystem of products, partners and integrations?This report provides eight case studies that illustrate the ways in which APIs have showed significant growth during the past year. We chose to focus on these particular APIs because they are all fairly recent examples, and they all have replicable strategies and can serve as a model for other API providers.When we talk about API success stories, we often speak of companies like Amazon, Twitter, Twilio, Context.io and SendGrid. There are some excellent resources that describe how these organizations are leading the pack. But, for new API providers, these success stories can be daunting and difficult to emulate. For this research, we chose to highlight API providers that are beginning to move beyond the startup phase and toward scaling up. We have identified the common elements of success that are helping these companies—which all showed strong signs of J-curve growth in 2014–build a vibrant developer ecosystem.