A system, methods, and apparatus for validating communications in an open architecture system are disclosed. In an example embodiment, a method includes selecting transactional information to transmit from a server to a communicatively coupled client device based on a request from the client device, selecting presentation information corresponding to the transactional information to transmit from the server to the client device, transmitting at least one message including the presentation and transactional information from the server to the client device, determining a prediction as to how the client device will render the transactional information based on the presentation information, receiving a response message from the client, and responsive to information in the response message not matching the prediction, providing an indication there is a malicious application affecting communications between the server and the client device.