Setting custom metadata in token

Hello everybody.

I have a requirement where a third-party app would like to authorize with our application. And while authorizing, they would like to send us a dynamic identifier in the access token which we would later use in each subsequent request.

They would like to set a custom scope with this dynamic identifier which we would read in our app. But, as far as I know, scopes can’t be dynamic, they need to be predefined in Auth0 dashboard (please correct me if I’m wrong). And scopes can’t be modified using actions, at least for now. Also, I’m pretty sure scopes are not meant for this kind of operation. They are a list of permissions that the client would use to request some protected resource from the resource server, so I want to avoid using scopes for this.

Another option is to use actions to set a custom claim, but the problem is that we would need to get that identifier from somewhere. We could query their API, but they would need to agree to build such an endpoint and we want to avoid that. Also, I’m not even sure if that’s doable on their side.

Another option that I’m considering right now is using actions to redirect a user to an external page and set that identifier there.

What would be the best approach for this? Should I continue with redirects or is there a better solution?

Hi @nemanja.milojevic,

Welcome to the Auth0 Community!

Yes, that is correct. Auth0 Actions cannot modify scopes. Auth0 Rules is capable of doing this, but we recently just announced the deprecation for Rules and Hooks coming soon, so this is not a future-proof solution. See the context.accessToken object for more details.

I recommend going with this approach with using Auth0 Actions to set a custom claim if this option is possible for you. I have shared a helpful resource below worth checking out: How do I make an Axios API call and store it as a custom claim using Actions? FAQ.

Yes, this is possible as well. When you use Redirect Actions, you will need to pass the dynamic identifier back to the authentication transaction to set the identifier in the Access/ID token.

May I ask if it is possible for you to set this dynamic identifier to the user’s metadata preemptively and then setting it as a custom claim when they log in?

I look forward to your reply.


Hi @rueben.tiow

Thank you for the response.

No, it wouldn’t be possible to set the identifier preemptively because each time they log in on their side we need to set an identifier, and it may be different each time. Unless there is a way to do that before logging in (they are using Authorization Code Flow)? I know we can set it in the user management, but again it can change over time.

I already started experimenting with the third option, and I think this should work for us.

Also, I was reading the articles you sent me and I saw that redirect actions won’t work with the refresh token exchange. That is fine, we want to execute the redirection only when they log in initially, but then each time they exchange the refresh token we need to set that same identifier in the access token. So we would need to have two flows:

  1. On login, redirect the user to the external page and set the identifier in the user metadata, which will be later set in token as a custom claim
  2. When exchanging refresh token, same identifier from the metadata would need to be set as a claim in the token

Is this possible?

Best regards

Hi @nemanja.milojevic,

Thank you for your response and clarification.

Absolutely! I can confirm that both 1. and 2. are indeed possible.

And as you have found, Redirect Actions will not work with a refresh token exchange. (Reference: Redirect with Actions)

In such a scenario, you can check if the user_metadata contains the identifier. If it does, you can proceed with appending it as a custom claim.

I hope this answers your questions!

Please let me know if you have any additional questions.


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