I applied online after clicking through a who's hiring post on Hacker News and submitting my resume and cover letter online. I was contacted the next day for a technical phone screen with one of the founders. When we talked on the phone, he started by asking me about projects I had built and technology that I had used and my ideas and motivation behind that. I discussed a web site that I had built and he asked me questions about web site performance and scaling and what techniques I would use to speed it up. I discussed caching and sharding in response. He then asked me details about the differences between programming languages and my preferences and understanding. I contrasted C and Python and discussed Python implementation details. He then asked me code a fibonacci number function (input n, output nth fibonacci number). I was nervous and wrote up an extremely naive recursive implementation and then struggled a bit with the the iterative implementation, but got through it with some prompting. After this, I was given a work sample problem to make a log parser that took data in their production log format and total unique visitors to certain url paths and also do funnel analysis on certain paths. I was told to write it in any language and I chose Python. They wanted to make it extensible, so I wrote some generic log-processing functions that took lambdas that did that actual computation specifics so all of the processing could use the same framework. In addition, I made the input format of paths be regular expressions to be matched. I don't recall precisely but I think this took three or four hours. Finally, I had a culture fit interview with the other co-founder where we discussed my general interests and the culture of the company, emphasizing the need to learn quickly.