As far as I know there is no upper limit of requests for DynamoDB. There is a default limit of 40.000 requests per second for provisioned capacity as well as for on-demand capacity, but you can get that increased upon request. See https://docs.aws.amazon.com/amazondynamodb/latest/developerg...

You might also want to read about the scaling behavior of DynamoDB On-Demand (https://docs.aws.amazon.com/amazondynamodb/latest/developerg...). Of course you can't immediately scale to any arbitrary request rate, but the way it's implemented sounds fine to me.

So do you have a source for your claim?