Google continues to innovate on the API front, today releasing an API in a very different category: charting. What is it? From the FAQ: "The Google Chart API is an extremely simple tool that lets you easily create a chart from some data and embed it in a web page. You embed the data and formatting parameters in an HTTP request, and Google returns a PNG image of the chart. Many types of chart are supported, and by making the request into an image tag you can simply include the chart in a web page." You can see more details on our new Google Chart API Profile here.
Steve Crossan from the Chart API team in Zurich notes via their blog that it's one of Google's simplest APIs yet: "Let's get straight in with an example. This URL creates this image:
"That's it - no state, no calls, just send your data in an http request and get a png image graph back. Embed the request in an img tag and you're done." He notes also this was built as a 20% project to support services like Google Video and Google Finance." Given that no API key is required, this is indeed a very easy API to start using right away.
Google does note there's a limit of 50,000 queries per user per day. But this is a reasonable constraint given that most charts can be generated and then cached on developer's own servers.