Callback setting in Sample Postman Collection

I am trying to run the sample Postman script described here:

For the authorize endpoint, I do not know what to set for the callback. Per standard OIDC, I assume I need to set the same callback in the authorization request as is in the OKTA application, right?

I saw one post describing the use of the Postman Interceptor, but I am still unclear.

Do I have to have another web app running at the same time to display the log in screen?

One site suggested using, but that did not work.

What should the callback be set to???

Thanks for any help

Also, for {{url}}/oauth2/v1/introspect, why does the collection set the user id and password to clientId and client secret? I see the id and secret are neede, but why are they put in the user id and pwd headers?

@kenshine Hi, please check the doc here for the callback setup.
To sign users in, your application redirects the browser to an Okta-hosted sign-in page. Okta then redirects back to your application with information about the user.
For /introspect, you can refer the request parameters in the API doc.
It includes the instruction of client_id and client_secret.