Backend Server Authentication for a Product


We are working on an app/product in which we would like to query the particle API. I’ve gone through the documentation on the authentication methods. What i am not seeing is a way to authenticate with an un-expiring token. I’ve done this in the past just using a client id and a client secret, but i only see in the documentation that it only creates an access token which can expire. This authentication will be used by the backend exclusively, and does not need to be shared with any customers. Additionally it will need full scope to the devices under that product, basically a “god token” for the product.

basically i would like to hit /products/{productId}/devices/{deviceId}/ unencumbered.

Any recommendations on how to proceed?