NodeJs and MongoDB dynamic database switching question.

So I am busy building a product and I want it to be multi-tenant, meaning for each user that signup I will create a new Database on my MongoDB cluster. Now the API is handled with one server, so I dynamically switch between databases depending on which user makes the request. Now I got it working 100% my question is how well does this scale? Considering that each user can make 100 requests per second multiplied by 10 000 users. Will nodeJS and MongoDB be able to keep up with that type of load and what performance hit will I get if any? Note: I have almost no experience building such large API's this is my first time so If I am completely missing the ball with what I am trying to do please let me know.