APIs are no longer a technical nice-to-have. Now APIs are a necessary business tool for startups to scale, much as Twitter and Facebook used theirs to reach more users. Your company wants to be on any new platform, but probably doesn't have a team that knows every last device. An API can help external development teams to bring your product to that new tablet, smart phone or TV. APIs can also speed up business development, even between startups and larger companies. With an API, partnerships become easier.