Hi , So you have created a Rest class and exposed it. At this stage you know how you can test this using Workbench. Ex: If your class name is : getAccountDetails which is expecting 2 parameters. then in the workbench, you will go to rest Explorer and select Get/Post based on the requirement and paste the URL something similar to this. /services/apexrest/CKDomain/getAccountDetails?Param1=1100055515&Param2=13706195 And BAM!!!! Everything looks fine. But in real time scenarios, you might want to give this endpoint URL to some other system (Say SAP/Oracle) and you want to test from your end before informing them about the endpoint URL. So how can we achieve this. There are many ways to test this and I prefer using Postman app for this. Install Postman from here. Now , In order to successfully receive a Rest call out from Other system to Salesforce , there are multiple auth techniques. I would like to use the most commonly used auth technique - OAuth 2.0 As per my k