curl "https://api.trusset.org/lending-stocks/api/positions/{marketId}/user-collateral/0xabc...def" \
  -H "X-API-Key: trusset_your_key_here"

{
  "success": true,
  "data": {
    "userAddress": "0xabc...def",
    "collateral": "100.000000000000000000"
  }
}