You don’t need to see 5,000 APIs to know some are better than others. One of the reasons is the attention the API providers have paid to the designs of their APIs. Below are three people summarizing popular approaches and helping you think about API design, whether you’re using someone else’s or planning your own offering.
Apperian encourages you to think about extensibility in the video embedded below:
Among the tips are to focus on the most scenarios and aim for self-documenting APIs.
Google’s Joshua Bloch has a great presentation (PDF). His general principles should not be skipped:
A good overview of common approaches to APIs. Includes explanations of HTTP GET/POST, *-RPC, SOAP, “REST” (yes, in quotes) and Hypermedia.
I’m sure there are many other great examples of API design best practices. I hope you’ll add your favorites in the comments.