A client-side flow control mechanism for controlling the flow of messages communicated from a service to a client in a remote access system. The service, which may be a managed or unmanaged service, may communicate messages to the client where the messages include a service sequence ID (SSI). As the client processes the messages from the service, the client responds with a client sequence ID (CSI). The SSI and CSI values determine the number of messages that are in transmission queues. The service compares a difference between the current SSI and CSI to a stop window value. If the difference is greater than the stop window value, transmission of messages from the service to the client is turned OFF. The client continues to send CSI acknowledgments as it processes messages. Once the difference falls below a start window value, the transmission of messages to the client is turned ON.