WePay Software Engineer, Backend interview questions

I applied through a recruiter and went through a phone screen. The phone screen was very simple for me but I can see how it would potentially weed people that wouldn't be the best fit. I came in on site twice and met with 4 people each time including one of the founders (for culture fit). The engineers gave me some tough questions and I was impressed at the back and forth in solving the problems. I felt very welcome and had a great experience.