I have TOKEN that a collection environment in Postman. I use it to set Authentication for all requests in this collection.

The flow goes like this:

1. Send login request from Postman
2. Retrieve the response and copy access_token value from the response body
3. Go to the collection environment manager
4. Set TOKEN variable value
5. Submit the other requests

I can see that Tests execute after the response is received. When you select Send, Postman runs your test script after the response data returns from the API so I use it to set TOKEN variable automatically.

I write this script for login request:

var jsonData = JSON.parse(responseBody);
pm.collectionVariables.set("TOKEN", `${jsonData.data.access_token}`);

After login success, I can see the TOKEN variable value has changed, so I can make the other requests.

Refs

• https://learning.postman.com/docs/writing-scripts/test-scripts/#writing-test-scripts