Arista's eAPI was first introduced in EOS 4.12 a few years ago. It transports a list of show or config commands over HTTP or HTTPS and responses back in JSON. An important distinction is that it is a Remote Procedure Call (RPC) and JSON-RPC, instead of the representation of state transfer and REST, even though the transport layer is HTTP(S). For our intents and purposes, the difference is that we make the request to the same URL endpoint using the same HTTP method (POST). Instead of using HTTP verb (GET, POST, PUT, DELETE) to express our action, we simply state our intended action in the body of the request. In the case of eAPI, we will specify a method key with a runCmds value for our intention.

For the following examples, I am using a physical Arista switch running EOS 4.16.