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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.

Hey there!

Sorry for such huge delay in response! We’re doing our best in providing you with best developer support experience out there, but sometimes our bandwidth is not enough comparing to the number of incoming questions.

Wanted to reach out to know if you still require further assistance?