Multiple clusters vs one cluster in MongoDB Atlas

Question

I am having multiple web apps that use MongoDB Atlas as their database. In Atlas, you can create Clusters that hold multiple databases.

For every web app, I usually need one database. However, I am not sure if I should create one cluster for every web app or only one cluster in total holding one database for every web app. Is there a better choice?

If I see right, then MongoDB's business model is to limit the free clusters capacities, which means that it would be better to create a free cluster for every web app, since otherwise the capacity of one cluster is consumed very quickly.

Answer 1

If I see right, then MongoDB's business model is to limit the free clusters capacities, which means that it would be better to create a free cluster for every web app

If this is correct (which seems to me like it is) then creating separate clusters per application is a good idea.

Once you are paying for your databases, it may be cheaper to put multiple databases in the same cluster (since you'll have less overhead per database).

A reason to use separate clusters per application when you are paying for databases is additional security/resilience to accidental database wipes.