Networks and methods for use in authenticating messages, based on the clients and the computing devices, are provided. One exemplary method generally includes performing, by an API gateway, validation of a computing device based on a certificate identifying the computing device as one of the recognized computing devices, via the repository, and performing, by the API gateway, validation of the client based on the client certificate via a global access manager, separate from the repository. The exemplary 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.