Hello @Bruce Harrison , currently this is not possible. As workaround you might create a middleware that add's any custom header to the B2C response.
Please take a look to the following development resources:
Interactive signin (recommended):
- Use the Microsoft Authentication Library for JavaScript to work with Azure AD B2C
- Use MSAL.NET to sign in users with social identities
Non-interactive signin (daemon/service/application):
- MSAL Username/password (ROPC)
- Microsoft Authentication Library for Node (msal-node)
- Configure the ROPC flow in Azure AD B2C with MSAL.NET
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