I would guess the pricing model is actually closely related to the main dimensions of their costs and is quite valid. The key point is illustrated by this quot

I would guess the pricing model is actually closely related to the main dimensions of their costs and is quite valid. The key point is illustrated by this quote from their main landing page: "storage and compute are decoupled, allowing each to scale independently". This suggests it is built on top of the Aurora storage layer, or something similar, as other comments have suggested. This means there is a real cost per I/O operation because you aren't limited by the physical hardware of the compute instances, you get "free" storage nodes underneath that do much more than traditional storage and thus have to be built into the pricing structure. It is definitely not going to be the cheapest possible solution for all use cases, but do the math before you reject it. If it does follow the Aurora pattern, then the number of I/O operations you are billed for will be a lot less than you may think because, to use another quote from their product page, "Amazon DocumentDB reduces database I/O by writing only database changes to the storage layer, avoiding slow, inefficient, and expensive data replication across network links". I think that quote is harder to understand without background as it sounds like market speak, but lines up very well with some of their in depth Aurora whitepapers, such as https://www.allthingsdistributed.com/files/p1041-verbitski.pdf https://www.allthingsdistributed.com/files/p1041-verbitski.p... Again, I haven't seen evidence this is based on Aurora but the details they talk about line up really well.