curl --request POST \
  --url https://arch-mainnet.gomaestro-api.org/v0/rpc/transaction/send/batch \
  --header 'Content-Type: application/json' \
  --header 'api-key: <api-key>' \
  --data '[
  {
    "message": {
      "instructions": [
        {
          "accounts": [
            {
              "is_signer": true,
              "is_writable": true,
              "pubkey": [
                123
              ]
            }
          ],
          "data": [
            123
          ],
          "program_id": [
            123
          ]
        }
      ],
      "signers": [
        [
          123
        ]
      ]
    },
    "signatures": [
      [
        123
      ]
    ],
    "version": 123
  }
]'

{
  "data": [
    "<string>"
  ],
  "last_updated": {
    "block_hash": "<string>",
    "block_height": 123
  }
}