1. A computer-implemented method for use in providing authentication of an application programing interface (API) message to a network, the method comprising: receiving an API message from a client, the API message including a client certificate; appending, by a computing device, the client certificate to the message as an object; appending, by the computing device, an intermediate certificate to the message, the intermediate certificate indicative of the computing device; transmitting, by the computing device, the appended messaged to an API gateway, the API gateway including a repository defining recognized computing devices; performing, by the API gateway, validation of the computing device based on the intermediate certificate identifying the computing device as one of the recognized computing devices, via the repository; performing, by the API gateway, validation of the client based on the client certificate via a global access manager, separate from the repository; and causing a security token indicative of the client to be generated, when the computing device is 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.