Yelp is a big organization and based on the data available on wiki, yelp has over $1 billion in revenue. So, if you are thinking to start a career at yelp you can visit their official website that is yelp career page for more information.

You can also reach out to people who are working at yelp on linkedin to know more about the company management, perks, work culture, etc.

At the end, I would say starting a career as a software developer at yelp is a good choice. You can also check yelp official linkedin page which has over 200k followers and there it is showing over 6k+ employees.