Dash is a small application which is actually a catalog of different APIs. You select which APIs to be downloaded and displayed. You could search within the downloaded APIs. You can integrate Dash to PopClip which is another useful application that could performs various actions with the selected text. You could also save your own code snippets. It is a free application but it tries to annoy you from time to time to convince you to purchase it. Today they have %60 percent discount so I decided not to be annoyed anymore. You can access all of these APIs online but it is good to have them in a common place.