curl --request POST \
  --url https://testnet.walletkit.com/transactions/batch-sign-and-send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "signer_wallet_address": "<string>",
  "unsigned_transactions": [
    {
      "to": "<string>",
      "value": "<string>",
      "input": "<string>",
      "gasLimit": "<string>",
      "maxPriorityFeePerGas": "<string>",
      "maxFeePerGas": "<string>",
      "nonce": "<string>"
    }
  ],
  "developer_secret": "<string>",
  "user_pin": "<string>"
}
'

{
  "transaction_id": "<string>",
  "status": "<string>"
}