I want to add dynamic OAuth Redirect URL

You should be able to add one or more OAuth RedirectURI's into your application during development ( Sandbox ).

Please Login to the Developer Portal and click on the application:

Head over to Settings -> OAuth Settings you should be able to add the redirectUri

For any OAuth Redirect URI additions into the application once the app has been approved for Production, please send out an email to the developer support team or submit a support ticket with the necessary details and the team would add it.

Hi Darshan,

Sorry, my bad I did not understand the question. I guess the usage of Wildcards will solve the purpose for you. 

Below is an example of how to use wildcards:

Let's say your redirectURI looks like this:

http://localhost:8080/callback.php

You could add the redirectUri on your application as:

http://localhost:*/callback.php

Let us know if you still have any issues using the Wildcards within the redirectURI.