curl --request POST \
  --url https://passkeys.hanko.io/{tenant_id}/transaction/initialize \
  --header 'Content-Type: application/json' \
  --header 'apiKey: <apikey>' \
  --data '
{
  "user_id": "<string>",
  "transaction_id": "<string>",
  "transaction_data": {}
}
'

{
  "mediation": "optional"
}