Abstract: An authentication platform for authenticating an online user is provided. The authentication platform includes a memory device including an authentication profile and at least one processor coupled to the memory device. The at least one processor is programmed to receive an authentication request message for a transaction. The authentication request message includes authentication data. The at least one processor is also programmed to extract the authentication data from the authentication request message and determine if the ACS is available to process the transaction. If the ACS is unavailable, the at least one processor is further programmed to generate, based at least in part on the extracted authentication data, risk-based authentication (RBA) result data including a risk score and transmit an authentication response message based on the RBA result data.