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API 101

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Application Programming Interfaces (APIs) are all around us. From posting a picture from Instagram to your Facebook page or clicking on a direct link on your favorite website to buying an item from Amazon, you spend a significant of time interacting with APIs and probably don't even realize it.

 What is an API?

In the simplest terms, an API is a way for one system to pull information out of another system.

As humans, we consume structured information in a variety of situations every day, such as:

  • Flipping through channel listings
  • Using a recipe to prepare dinner
  • Reviewing bus schedules
  • Checking the scores of last night's game

For each of these, we know what to expect because of the information's structure:

Check out GSA’s video on what APIs mean for the federal government.

  • The channel listings contain the name, time, and a short description of the program
  • Recipes contain ingredients, measurements, and instructions
  • Bus schedules tell you the route number, stops, and times
  • Game scores list the sport, team names, and final scores

Online services also take advantage of structured information. For example, when you look up a restaurant on a smartphone, you can click on the address and you'll automatically get directions to the eatery in your phone's navigation program. In this example, the API in your smartphone knows what the address is (a place on a map) and that you'll probably want to get there from where you are now. It takes out all the hard work, so you can focus on eating!

All of these tasks use an API. APIs provide structure to information so computers can use and understand that information, the same way you use and understand a recipe or bus schedule in a single glance.

Why are APIs important?

By adding structure to information, you can find what you're looking for quickly. APIs are especially valuable because they enable developers and entrepreneurs to create applications that sort, package, and serve up information in different ways—creating new tools and programs using the same information.

Integrating information from multiple sites can make your content more powerful. Consider Google Maps. Google Maps has integrated the Wikipedia's API, enabling you to get information from Wikipedia alongside the Maps' information when you look up a place and select "Wikipedia" from the menu. There are millions of these types of applications and reasons for combining content APIs.


Currently, HHS offers 32 APIs on subjects from biomedical research to health care costs. Our Healthcare Finder API helps the public find health insurance that is best suited to their needs. Whether they are looking for private insurance for individuals, families, or small businesses, or public programs that may work for them, heathcare.gov shows the public which insurance might be best for them.

Visit www.healthdata.gov. Tell us what datasets you think should be API-enabled and explain how the data might be used. [Note: on www.healthdata.gov, you can also tell us health datasets you’d like to see added.]

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Submitted by Anonymous on
I understand how important the APIs have!! I did not know the information about APIs but I have heard the word"APIs" several times, but Now I know what and how it works. Thanks for letting us know.