Have you tried looking up questions for that company on Glassdoor or Google? Every team and interviewer is different, especially when you move into the start-up world. That said, you might be able to find questions for the company on Glassdoor.
Overall, your best bet is to talk to the recruiter to clarify expectations around the interview process. They should want to help you prepare and give you clear expectations, especially if this is a place you would want to work. Most recruiters would also take this as a positive sign that you are interested and taking their interview process seriously.
Beyond that, general interview preparation (e.g. understanding algorithms and data structures) is always important. Also, especially for a start-up, look at the role you applied to and be ready for questions related to the requirements and responsibilities of the role.
At a high-level:
Now let's talk preparation techniques:
Wrapping it all up, the following are much more important tactically for startup interview prep:
For getting the interview to begin with, check these out: