If you are testing REST APIs application with Oauth on Postman, generally you do the following, Send a OAUTH request to an /auth endpoint and copying the access token, and setting header as ‘Bearer <access-token>’ in actual request. This copy-paste be avoided if you set following in This will execute the Oauth request before executing the actual REST API, and store in a global variable. So consecutive calls will utilize the stored global variable. pre-request script pre-request tab Above works great for a single cluster setup. However for a multi cluster setup, where you have one cluster in say EU data center, another in US, then you would need to duplicate this setup. I have seen developers Postman flooded with hundreds of similar requests, with only change being the URL, like below with over 184 requests This can be avoided by using . environment variables I have modified the to store the access tokens, refresh token as a value object in a map with key being the cluster url. This url is set via the environment variables. pre-request script So now I can switch to different clusters easily by switching the environment.