API U Series

What Are APIs and How Do They Work?

When it comes to the application programming interfaces (APIs) and the API economy, the only question that gets asked more frequently than "Why do I need APIs?" is "What is an API?" Thanks to the wider-spread attention that APIs are getting from the mainstream media, "What is an API?" is in fact the million dollar question because for those who understand the potential of APIs, there could be millions of more dollars to be made, or saved.

Answering in a relatively comprehensive but cogent fashion can not only help developers to be more contemplative about fully leveraging the promise of APIs in their wares, it can really jumpstart the conversation that needs to take place between (1) business stakeholders looking for new opportunities and operational efficiencies and (2) the technical staff that's chartered with turning an organization's compute infrastructure into a reflection of the go-forward strategies and objectives. Therefore, establishing a common understanding of what APIs are, how they do what they do, and what some of the most important benefits are is central to moving that conversation forward in a meaningful way.

In creating this seven part series on What are APIs and How Do They Work, ProgrammableWeb editor-in-chief David Berlind turns to some very commonly known real-world metaphors so that readers can more easily understand how APIs fit into our world, what they're used for, and the sorts of opportunities that are unlocked by their underlying architectural principles of standards and abstraction.

In debating what metaphors were applicable, it became clear that none were perfect (somewhat proving the highly unique value proposition of the API). However, some make the power of APIs easier to visualize even if a liberty or two has to be taken in order to bring certain points home. For example, in comparing APIs to electrical wall sockets, the service provider isn't exactly responsible for the last mile of wiring right up to the socket. But, if you'll allow David a few such liberties, his explanation is sure to empower you with a command of the API domain that will be useful in just about any context from consuming developers to API providing organizations.

Finally, this series is one of several that we consider a part of the core curriculum to ProgrammableWeb's API University. As we look to expand this core curriculum (as well as all of the content that API U hopes to offer), it is also our intention to revisit these series and improve both their content and presentation. To that extent, we welcome suggestions and look forward to your feedback in an effort to ensure that ProgrammableWeb is the ultimate destination for maintaining your understanding of the API economy.

Whenever the mainstream business media starts to cover a technology as though it is some sort of wonder drug (like it has for APIs, or application programming interfaces), it creates a groundswell of curiosity. People want to know what exactly the wonder drug is? How does it work? How might it...
This is the first part of our series What Are APIs and How Do They Work?. If you missed the introduction to this series -- APIs Are Like User Interfaces--Just With Different Users In Mind -- we strongly suggest you start there first. In this second part of our series, we will define the million...
This is the second part of our series What Are APIs and How Do They Work? In part 1, we used the standard electrical socket found in most walls as a metaphor for explaining the principles of an API. Imagine what life might be like without such a standard. For example, with no plug,...
This is the third part of our series What Are APIs and How Do They Work? In part 2, we covered some of the key benefits of APIs. First, let’s review the primary constituencies impacted by APIs, starting with computer programmers, also known as application developers. APIs Make Developers More...
This is the fourth part of our series What Are APIs and How Do They Work? In part 3, we went deep on how Web and browser APIs make the Web programmable while fueling what’s known as the API economy. When an API’s endpoint is architecturally the point at which the API-consuming application is...
This is the fifth part of our series What Are APIs and How Do They Work? In part 4, we focused on the API concept of abstraction and the type of flexibility it creates for API providers. While there are no rules or laws governing exactly how developers must connect their applications to an API from...
This is the conclusion of our series What Are APIs and How Do They Work? Making certain functionality--be it the results of a database query or interactive functionality like a map--available via API dramatically changes the way that software technology and information can be delivered to the...