I applied in-person. The process took 3 weeks. I interviewed at Duo Security (Austin, TX) in Nov 2017
Interview
First there is a phone call with the hiring manager to discuss the role in more detail and answer any questions. Second there is a technical phone screen where you are given some coding challengers. If that goes well then you are invited to interview in the office with multiple people. The in-person interview consists of coding challengers, behavioral questions, and lunch with some team members.
Interview questions [1]
Question 1
They asked technical questions similar to those you would find on HackerRank.