Had two interviews.
The first was over the phone, as the CTO works out of the NYC office. Spoke mostly with the CTO, who asked my knowledge of certain technologies, libraries, frameworks (see below). Had a chance to chat with him about business topics (e.g., vison, product line, business model), and the company's strategy for design (which was not done in-house at the time of my interview).
This first interview was more casual.
Second interview was in-person, with HR and a senior developer (technical interview).
Since the company had no front-end devs at the time, this developer (a mobile specialist, IIRC) was forced to rely on predetermined questions. We navigated through the specifics of Angular, then he asked some generic interview questions.
I had a chance to ask them questions at the end — so a pretty standard (though probably a bit dated) interview format, in that the second interview could have been more casual. To be fair, that would be tough to do without already having a team with the same expertise as the candidate.
I also requested to chat with the CTO again after receiving an offer, and had another excellent, relaxed conversation with him.