MongoDB uses lot of RAM, so choose wisely. And in certain cases it’s slow compared to other No-SQL system. Now there will be no standards across your projects, because there is no structure to data and all projects will be using different No-SQL db that is suitable for its need.

Why is MongoDB not good?

One of the downsides of MongoDB is that it doesn’t support transactions. Though fewer and fewer applications are requiring transactions, there are still some that need transactions in order to update multiple documents/collections. If that’s a necessary function for your team, MongoDB should not be used.

Where is MongoDB not suitable?

MongoDB would not be well suited for applications that need: Multi-Object Transactions: MongoDB only supports ACID transactions for a single document. SQL: SQL is well-known and a lot of people know how to write very complex queries to do lots of things.