curl --request POST \
  --url https://api.gputrader.io/v1/rentals/checkout \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '{
  "returnUrl": "<string>"
}'

{
  "id": "<string>",
  "client_secret": "<string>"
}