curl --request POST \
  --url https://api.starkfi.io/security/wallet/challenge \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api_key>' \
  --data '{
    "wallet": "FmTGYpzX27fDqaiytXUdFVaphC5o68G61Q3uhVM2d8bm",
    "purpose": "kyc"
  }'

{
  "statusCode": 201,
  "success": true,
  "status": "challenge_created",
  "message": "Sign this message with your wallet",
  "data": {
    "message": "StarkFi KYC verification\nWallet: FmTGYpzX27fDqaiytXUdFVaphC5o68G61Q3uhVM2d8bm\n...",
    "wallet": "FmTGYpzX27fDqaiytXUdFVaphC5o68G61Q3uhVM2d8bm",
    "wallet_chain": "solana"
  }
}

{
  "statusCode": 400,
  "success": false,
  "status": "invalid_wallet",
  "message": "Wallet challenge failed"
}