curl --request POST \
  --url https://api.contribyard.com/v1/passkey_attestations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "attestation": {
    "user_id": "<string>"
  }
}'

{
  "response": {
    "id": "<string>",
    "credential_creation_options": {}
  }
}