curl --request POST \
  --url https://xbt-mainnet.gomaestro-api.org/v0/mempool/transactions/send \
  --header 'Content-Type: application/json' \
  --header 'api-key: <api-key>' \
  --data '
{
  "tx_hex": "<string>"
}
'

{
  "txid": "<string>"
}