curl --request GET \
  --url https://arch-testnet.gomaestro-api.org/v0/rpc/block/{height_or_hash} \
  --header 'api-key: <api-key>'

{
  "data": {
    "bitcoin_block_height": 123,
    "hash": "<string>",
    "height": 123,
    "merkle_root": "<string>",
    "previous_block_hash": "<string>",
    "timestamp": 123,
    "transaction_count": 123,
    "transactions": [
      {
        "accounts_tags": [
          "<string>"
        ],
        "bitcoin_mined_time": 123,
        "bitcoin_txid": "<string>",
        "hash": "<string>",
        "runtime_transaction": {
          "message": {
            "instructions": [
              {
                "accounts": [
                  {
                    "is_signer": true,
                    "is_writable": true,
                    "pubkey": [
                      123
                    ]
                  }
                ],
                "data": [
                  123
                ],
                "program_id": [
                  123
                ]
              }
            ],
            "signers": [
              [
                123
              ]
            ]
          },
          "signatures": [
            [
              123
            ]
          ],
          "version": 123
        },
        "status": "<unknown>"
      }
    ]
  },
  "last_updated": {
    "block_hash": "<string>",
    "block_height": 123
  }
}