How to check if a user is linked to an external identity provider?

FASupportBot

I need to determine whether a user is linked to an external identity provider to change application behavior accordingly. I've checked the user object in the userinfo lambda and the /api/user/{userId} endpoint, but neither contains information about linked identity providers.

When attempting to use the /api/identity-provider/link endpoint with just a userId parameter, I receive this error:

You must specify the [identityProviderId] property. During a [POST] request this property is not required when using the [pendingIdPLinkId] property to complete the link request.

Is there a way to:

Get a list of all linked identities for a specific user?
Determine during login that the user authenticated via an external provider?

I'm using FusionAuth 1.69.2 and authenticating with an API key.

FASupportBot

You can retrieve all identity provider links for a user by sending a GET request to:

/api/identity-provider/link?userId={userId}

Important: The parameter name is case-sensitive and must be userId (with capital "I"), not userid.

The error you're seeing occurs when the parameter is lowercase userid instead of the correct camelCase userId. Using the correct casing will return a list of all identity provider IDs that the user is currently linked to.

Make sure your request looks like:

GET {baseUrl}/api/identity-provider/link?userId=4aa40fcd-0102-4c26-a51c-9a6c5c0c504a
Authorization: <your-api-key>

This endpoint works with a standard API key and will return the identity provider link information you need to determine if a user is linked to external providers.