An example system receives certificate requests from clients. Each request can indicate a number of computerized devices needing certificates; a timestamp indicating when the request was transmitted; and a client identifier. The system includes a Quality of Service (QoS) manager that: distributes the requests from the clients across client queues, each of the client queues corresponding to a particular client; and divides requests into smaller subgroups of entries corresponding to a subset of the computerized devices needing certificates. The system can also transmit retrieved entries from the client queues to a certificate management service.