BGG API How-to Guide
What is BoardGameGeek?
BoardGameGeek has often been referred to as "the IMDB of board games". If you want to learn anything and everything about board games, and interact with the hobby's most dedicated enthusiasts, BGG is the place for you.
BoardGameGeek is an online board gaming resource and community. The site is updated on a real-time basis by its large and still growing user base, making the 'Geek the largest and most up-to-date place to get gaming information! There is no charge to become a registered member of BGG, although you are certainly encouraged to help improve the site by adding your own reviews and thoughts on games to the existing database!
There are reviews, ratings, images, play-aids, translations, and session reports from board game geeks across the world, as well as live discussion forums. In addition, every day nearly a hundred game trades pass through the hands of registered members, as well as transactions in the marketplace. If you are new to the site and are wondering where to begin, you might start with the Guide to BoardGameGeek.
Official BGG welcome page:
In addition to boardgames, BoardGameGeek also supports two other offshoot sites: VideoGameGeek.com and RPGGeek.com - Both of which contain data accessible through BGG's API.
What is an API?
API stands for Application Program Interface. I like this concise definition of an API given by a user on the popular site Reddit.com:
As opposed to a User Interface (UI), an API is an interface that is designed to be used by other applications. For example, Google Maps has a UI (which takes input via a zoom slider, a position bar, etc operated by mouse clicks), and an API (which takes input as text, commands, or coordinates directly from another program). The UI is designed to deliver images as output (human readable). The API is designed to deliver chunks of text and arrays as output (machine readable).
Reddit.com user intensely_human
In short, an API allows you to get data from or send data to an application. You can use data obtained in this way to build other apps. Just like Twitter and Google Maps have APIs, so too does BoardGameGeek.