It is best practice to protect APIs with OAuth. All the big API providers use it, such as LinkedIn, Google or Paypal.
But it is not easy to use OAuth correctly! OAuth can be outright confusing. I got confused when I was trying to use it for the first time. And I see the same happening to many of my colleagues, when they have to use OAuth before calling an API. That is why I have created the OAuth 2.0 Cheat Sheet!
After Signup to the API Best Practice Newsletter you will get the OAuth 2.0 Cheat Sheet. You can print it and stick it next to your desk, so you will never get confused by OAuth again.