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

"<string>"