Google presents lots of instruments for web-designers / developers and almost all of them has their API interface to simplify integration with other services.
If you often use these services and API, then probably you’d like to have the oppotunity to get any description as soon as possible, and not to search for necessary information. There is a special page for this, which is called «Google APIs & Developer Products«.
There are all groups of Google services, which can be useful for programmers, listed at this page. It’s 100% must-have tab for those which are deal with web-developing!