Networks and methods for use in authenticating messages are provided. One exemplary method generally includes receiving a message from a client, where the message includes a client certificate. The method also includes validating, by an application programming interface (API) gateway, a computing device based on a certificate identifying the computing device as a recognized computing device, and validating, by the API gateway, the client based on the client certificate via a global access manager, separate from the repository. The method further includes causing a security token indicative of the client to be generated, when the computing device and the client are validated, whereby the security token is indicative of the client and permits the message, from the client, to be delivered to one or more backend services.