Systems and methods of site traffic control are disclosed. In some example embodiments, a first request for an online service to perform an operation is received from a first user on a first client device, and at least one overload condition for the online service is detected, or otherwise determined, with the overload condition(s) corresponding to a first request time of the first request. A first token and a first return time parameter for the first user are determined based on the determination of the overload condition. The first token and the first return time parameter are transmitted to the first client device.