2 phone interviews - 1 with HR and 1 with CTO. In-person meeting was 4 hours. 2 with Founder/Managing Partner. Then follow-on 2-hr lunch with CTO, HR, and Founder. Before interview started they gave me an exercise to solve 2 PHP codebase issues and then to write a sample email to example the issue/resolution. They only gave me 15 minutes. When asked audience of the sample email, the did said it was open-ended to my preference. Lunch interview had them discussing with me my sample email and audience etc.