Web APIs are not meant to be presented in nice layout, such as websites. Instead, most web APIs return data in a structured format, such as JSON or XML. Having data in a structured form has the advantage that the data can be easily processed by other tools, such as . For example, the API from returns data in the following JSON structure.

Some web APIs return data in a streaming manner. This means that once you connect to it, the data will continue to pour in forever. A well-known example is the Twitter “firehose”, which constantly streams all the tweets being sent around the world. Luckily, most command-line tools that we use also operate in a streaming matter, so that we also use this kind of data.

$ curlicue-setup \
> 'https://api.twitter.com/oauth/authorize?oauth_token=$oauth_token' \
> credentials

For more popular APIs, there are specialized command-line tools available. These are wrappers that provide a convenient way to connect to the API. In Chapter 9, for example, we’ll be using the command-line tool bigmler that only connects to BigML’s prediction API.