SSO URL
By default, authorization method used for SSO is Implicit grant which attaches user pool tokens ( id_token, access_token, expires_in and token_type ) to the redirect_uri once the user is verified. The id_token then can be used when Single Sign On server as authentification for license user in License Activation
If you do not wan't to expose user tokens or the redirect uri is too long for your use case, you can use Authorization code grant method where instead of id_token the code query param is attached to the redirect_uri and this code is sent instead of id_token on request body when doing license activation. To enable Authorization code grant attach the optional response_type=code query param to this endpoint. Example:/api/v4/sso_url/?customer_account_code=test&product=test&response_type=code
More informations about AWS Cognito grants can be found here