curl -X POST https://api.sw4p.io/sdk/v1/estimate \
  -H "Content-Type: application/json" \
  -H "X-API-Key: sk_..." \
  -d '{
    "from": "BASE",
    "to": "SOLANA",
    "amount": "100.00"
  }'

{
  "amount": "100.00",
  "fee": {
    "total": "2.50",
    "platform": "1.00",
    "gas": "1.50"
  },
  "net_receive": "97.50"
}