Systems and methods for authenticating an electronic transaction using a hosted authentication service. The systems and methods determine whether an authentication is required based on a first electronic message received from a first data system. Upon determining the authentication is required, the systems and methods transmit a dummy authentication request and a hosted authentication service uniform resource locator to the first data system. The systems and methods further determine or receive an indication whether a user authentication challenge is required based on a transaction risk analysis by a second data system. Upon determining the user authentication challenge is required, the systems and methods provide, at a user interface, an electronic form including a challenge request. The systems and methods transmit, to the first data system, another electronic form including a dummy authentication response generated based on a challenge result.