Reducing concurrency in a system comprising a plurality of services sending a plurality of concurrent requests to a back-end service through a concurrency reduction service. The concurrency reduction service maps each concurrent incoming request to a key; and determines if the key to which the concurrent incoming request is mapped matches a key mapped from another concurrent incoming request from the plurality of concurrent requests. If the key to which the concurrent incoming request is mapped matches a key mapped from at least one other concurrent incoming request from the plurality of concurrent requests, then the service groups the concurrent incoming request with the at least one other concurrent incoming request to be sent to the back-end service. The concurrency reduction service sends one outgoing request to the back-end service for each of the keys to which the plurality of concurrent incoming requests were mapped.