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Postman Failed - Get New Access Token via Implicit Grant

How do I use Postman to get an access token with an implicit grant so that I can test my application API? I’m using SPA + API. My API is Node.js with ExpressJS.

The Postmain main.log shows “URL did not match the registered callbackURL” when I enter the username and password on the login screen displayed by Postman.

But I make sure the Auth0 Allowed Callback URLs match the Postman login flow. I have tried all of the following Callbacks and all fail with same result. I have compared what is listed in log to what I enter in the Postman implicit flow to what is in Auth0 config. All seemingly match.


Additionally, Postman console shows 403 after submitting username/password. I’m not sure why.

I originally got this to work on my first try about a week ago by following this Auth0 blog post and using the implicit flow, and then the next night I used the logout endpoint to logout the user so that I could go through the implicit flow again to request a new token. Since then this has not worked again with Postman and I have spent several nights reading through all the articles, blogs, and api doc with no success.

Any help is extremely welcome.

I did find a workaround to use the Authentication API Debugger to get an access_token, manually copy it into Postman, and then call my application API however this is tedious. I’d rather get this all working in Postman so that I can better test my backend.

Thanks in advance.