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There will be times when a user updates credentials to their connected services account. When this happens, the user will need to go through Connect again to update your authorization through Smartcar. You can do this with a streamlined Connect flow using a special re-auth URL with the parameters below.
Re-authentication is also required when OEMs migrate to new API platforms. See OEM Migrations and Re-authentication to understand when and why these migrations occur, and how to prepare your implementation.
The AUTHENTICATION_FAILED API error contains a partially constructed re-authentication URL in the resolution.url field.

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application_id
string
required
The application’s unique identifier.
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redirect_uri
string
The URI a user will be redirected to after authorization. This value must match one of the redirect URIs set in the credentials tab of the dashboard.Required if response_type is set to vehicle_id. If response_type is set to none, this parameter is optional: if you do not set a redirect URI, the flow ends on a Smartcar-hosted completion page.The first redirect URI you add to your application is automatically set as the default. If you do not specify a redirect_uri in your Connect URL, Smartcar will use this default URI. You can add multiple URIs and set any of them as the default in the Smartcar Dashboard.
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response_type
string
required
This value must be set to vehicle_id or none. In both cases, the vehicle_id and external_id (if provided and is valid) are returned as query parameters in the redirect back to your application.
  • vehicle_id: redirect_uri is required.
  • none: redirect_uri is optional; if you do not set one, the flow ends on a Smartcar-hosted completion page.
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vehicle_id
string
required
The id of the vehicle you are reauthenticating.
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state
string
An optional value included as a query parameter in the redirect_uri back to your application. This value is often used to identify a user and/or prevent cross-site request forgery
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external_id
string
Your application’s own identifier for the vehicle owner. See the Connect URL reference for validation rules and where the value is surfaced.This parameter is optional, but we strongly recommend setting it on every Connect session, including re-authentication. The stored value is replaced by the external_id of the new session; re-authenticating with external_id=null clears it.
HTTP/1.1 302 Found
Location: https://connect.smartcar.com/oauth/reauthenticate?
  response_type=vehicle_id
  &application_id=8229df9f-91a0-4ff0-a1ae-a1f38ee24d07
  &vehicle_id=sc4a1b01e5-0497-417c-a30e-6df6ba33ba46
  &redirect_uri=https://example.com/home
  &state=0facda3319
  &external_id=customer-user-abc123