curl --request POST \
  --url https://testnet.walletkit.com/transactions/sign-message \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "network": "Ethereum",
  "message_type": "string",
  "signer_wallet_address": "<string>",
  "message": "<string>",
  "developer_secret": "<string>",
  "user_pin": "<string>"
}'

{
  "signature": "<string>"
}