Sam Hall doesn’t just eat his own dog food, as the Silicon Valley saying goes. He also orders it on his mobile phone.

As vice president of mobile shopping at the world’s largest online retailer, Hall is in charge of making sure it’s easy, and very fast, to shop on Amazon using its apps and mobile websites. His mantra is that people should go from “wanting to buying in 30 seconds,” and Hall is a compulsive tester of the process, using his phone to buy basketball hoops, dental floss, shampoo, and even a gorilla costume for Halloween.    

Mobile shopping is still a sliver of overall retail, and of Amazon’s revenue. While the company doesn’t divulge details, analysts think that maybe 8 percent of the company’s $61 billion in annual sales come from phones and tablets. But Hall’s domain is growing as more people use smartphones and tablets. Amazon runs a slew of mobile apps, including the basic Amazon Mobile shopping app. There’s also Flow, which pulls up price information (and a chance to buy on Amazon instead) for any product you aim your smartphone’s camera at.

Amazon is tight-lipped about its operations and plans, and Hall is no exception. MIT Technology Review spoke with him about his work.

What’s the big thing on your mind these days?

I spend most of my time worrying about how we continue to invent, on behalf of our customers, newer, faster, better, easier ways that they can shop on their mobile phones and tablets.

You’ve said Amazon wants to shorten the time between wanting and buying an item to less than 30 seconds. How short can it get?

We believe that customers want the time from wanting to buying to be as close to instant as possible.

How do you do this, technologically?

We are very, very focused on making sure our experiences are fast. That every page loads quickly—from the time you press the icon on your phone to the time you see a search box, it’s very, very quick. For instance, we focus on input. We know one of the hardest things about shopping on a mobile device is just inputting what you want.

What is an example of how you design for that?

When you��re typing in something in the search box, we put up search suggestions very, very quickly. Earlier this week, I ran out of razor blades. I use Gillette Fusion razor blades. I was able to type “gil” and one of the first few suggestions that came up was Gillette Fusion razor blades. I only had to type the first three letters of what is probably a 26- or 27-letter title to quickly get to that item.

Some researchers are working on software that tries to actually anticipate what a person wants. Is Amazon involved in this type of research?

What I can say is, we have a search team that focuses specifically on the very fastest way we can get customers from typing in what they want to the detail page of what they actually want.

What are the most surprising things you’ve learned about people’s shopping behavior on mobile devices?

I think people tend to assume there are certain categories that do better on mobile than others, but the reality is, customers are buying everything on their mobile phones. We’ve sold, believe it or not, engagement rings, bicycles, razor blades, jeans, dresses. People buy the whole variety of what Amazon has.

Another recent observation that’s been interesting is that one of our busiest days happens to be on Christmas Day, for mobile phones and tablets in particular. My theory, at least, is you open up all your presents, you didn’t get what you want, and you’re able to quickly buy what you really wanted for Christmas.