How to integrate Google Smart Home API with your IoT devices?

To begin you need to make sure your server has OAuth implemented for linking accounts. Google works with an Authentication URL to get an authorization code and a Token URL to get access token or refresh the token. These tokens are added to the API header which lets Google operate IoT devices through your server. Google highly recommends using opaque symmetric encrypted access token as it can only be decoded by an authorization server unlike JWT token which consists of the user information.