Logging in to an SPA , preauthenticated by another application

Hi All, wondering if there is an out of the box solution for this.

We have an SPA that we host that is secured using Auth0. Users are added to an Auth0 database and can login using the universal login screen, a username and a password, they have to be created in the Auth0 database first.

Separately, we have another legacy application that is hosted in a different way and is not using Auth0 for user logins. It maintains its own database of users, and these users are not set up in Auth0. I would like to be able to give access to these users to the Auth0 managed service somehow. I am thinking there might be a way of using an M2M token for this application to generate a token to give to the user, who once redirected to the service, would not need an additional login.

Does anyone know if such a thing is possible?

It is possible to integrate your legacy application with Auth0 using a combination of approaches, and there are out-of-the-box solutions available:

Migrating Users to Auth0

Partial Migration to Auth0

  • If you want to keep your existing authentication pipeline and gradually move parts over to Auth0, you can create newer parts of your application with a .NET CORE API using Auth0 and move parts over piece by piece Question about implementation of legacy applications

Integration via M2M Token

  • To give access to users from the legacy application to the Auth0 managed service without requiring an additional login, you can consider using a Machine-to-Machine (M2M) token for this application to generate a token to give to the user. Once redirected to the service, the user would not need an additional login

there are methods available to integrate your legacy application with Auth0 and provide access to users through the Auth0 managed service without requiring them to be set up in the Auth0 database. You can leverage strategies such as partial migration and M2M tokens to achieve this integration.