A connection-aggregation proxy service disclosed in various embodiments receives connection requests from a plurality of local initiating services, where the connection requests are not targeted at the connection-aggregation proxy service. The connection-aggregation proxy service establishes connections with the local initiating services, receives packets over those connections, and transmits the packets across the same connection when the packets are for the same external target. A local connection-aggregation proxy service in one example executes on the same physical computing device as the local initiating services. A gateway connection-aggregation proxy service in another example resides at a network edge between the local initiating services and the external target that the network local initiating services are requesting. In yet another example, a central connection-aggregation proxy service establishes a connection with multiple local connection-proxy aggregation services and acts as an upstream aggregator for the connections from those local connection-aggregation proxy services.