I applied online. The process took 2 weeks. I interviewed at Amazon
Interview
I went through two coding challenge interviews. The first was half multiple choice, half debugging. They were pretty simple and straightforward. The second was a bit more challenging but doable if you don't panic.
I applied online. The process took 4 months. I interviewed at Amazon in Feb 2017
Interview
I applied to Amazon for a summer internship. They got back to me around 2 months later with an online debugging section and logic quiz. The debugging was a matter of double checking if signs were the right way (<, >) and double equals instead of equals, stuff like that. The logic was trickier. Then an online programming quiz where they asked a few standard questions.
Applied online, was given problems to solve in a coding challenge. Wasn't particularly hard. The questions were relatively straightforward, but I made a basic mistake and got stuck on a bug.