Auth0 Callback URL not Called in Blazor Server Application

I have a .NET Blazor Server application with Auth0 hooked up and 95% working. The part that isn’t working, and perhaps I have this wrong, but the callback I’ve specified isn’t being called after a successful login. The application instead just redirects to my home page (Index.razor).

What I expect the application do is redirect me to my callback where, in theory, I can perform additional logic around the user. This would be things like:

  • Logging the successful user login
  • Creating a user account in my DB (where I track their preferences, etc.)
  • Setting additional user context with meta-data from my DB
  • etc.

I’ve set the callback path in my Program.cs file via the Builder.Services delegate (this actually fixed an error message when wiring up the application initially), but when I create a razor page (callback.cshtml) and it’s corresponding OnGet() function, no code in that method ever gets called.

Am I doing something wrong? Does anyone have an example of a working callback page (both markup and code behind, if necessary) that I can try out?


Hi @cellaret

Thanks for getting in touch with us at Auth0 Community.

I would recommend you review this if you haven’t already done so.

I’m assuming you’re using the Auth0 ASP.NET Core Authentication SDK which is a wrapper around OpenId Connect. The /callback isn’t necessarily a page you need to create but it gets processed internally by the OpenId Connect middleware. After successful auth most likely you will be returned to your homepage. I expect from there you may call other aspects of you application to do whatever custom processing is required.

Warm regards.

I have read it and have implemented it successfully wherein my application redirects to the home page.

I do not want, however, my application to redirect to my homepage. I want it to redirect to a callback page to do any post login logic/processing. The index page is not the proper page to do any of that. If I implemented this pattern (or anyone for that matter), every time someone visits the home page, that post-authentication logic would get executed. This is unnecessary.

I’d like an example of how one might implement a proper authentication callback in Blazor. Searching the web is proving difficult as the SDK obfuscates (as it should) the necessary plumbing a callback would need. If additional plumbing is needed in the Startup.cs file (or any additional files) to wire up a callback, that would be super helpful.


Hey @cellaret,
I redirect this thread to our other thread in case other people have the same question.

1 Like

For future reference @andrea.chiarelli I believe you can also merge topics into one to make it easier to navigate!

1 Like