I applied online and got reply from the recruiter quickly.
First I had a 30-min phone screen with the recruiter, discussing my work experience and interests. Two weeks later, I had the phone interview with a senior software engineer, still discussing my experience(but to more specific details), as well as the technologies they were using.
This company is great and their products are very interesting. Unfortunately my current work experience is not a good match to their back-end challenge handling. The recruiter is very nice. Great experience communicating with this company.