curl -X POST https://api.fincept.in/user/register \
  -H "Content-Type: application/json" \
  -d '{
    "username": "yourname",
    "email": "your@email.com",
    "password": "SecurePass123!"
  }'

curl -X POST https://api.fincept.in/guest/create \
  -H "Content-Type: application/json" \
  -d '{"device_id": "test-device"}'

curl -X POST https://api.fincept.in/cashfree/create-order \
  -H "X-API-Key: fk_user_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "plan_id": "credits_500"
  }'

{
  "success": true,
  "data": {
    "payment_url": "https://payments.cashfree.com/...",
    "session_id": "session_abc123",
    "amount": 449
  }
}

curl https://api.fincept.in/user/profile \
  -H "X-API-Key: fk_user_your_key"

{
  "success": true,
  "data": {
    "username": "johndoe",
    "account_type": "free",
    "credit_balance": 284.5,
    "created_at": "2024-01-15T10:30:00Z"
  }
}

curl https://api.fincept.in/user/usage \
  -H "X-API-Key: fk_user_your_key"

{
  "success": true,
  "data": {
    "period": "last_30_days",
    "total_requests": 127,
    "total_credits_used": 65.5,
    "current_balance": 284.5,
    "endpoint_usage": {
      "/quantlib/pricing/black-scholes": {
        "count": 45,
        "credits": 90
      },
      "/quantlib/risk/var": {
        "count": 5,
        "credits": 25
      }
    }
  }
}

{
  "success": false,
  "message": "Insufficient credits",
  "detail": "Required: 5 credits, Available: 2 credits. Please purchase a new plan to continue."
}

# Step 1: Create checkout
curl -X POST https://api.fincept.in/cashfree/create-order \
  -H "X-API-Key: fk_user_your_key" \
  -H "Content-Type: application/json" \
  -d '{"plan_id": "basic_monthly"}'

# Step 2: User completes payment at returned URL

# Step 3: Check updated balance
curl https://api.fincept.in/user/profile \
  -H "X-API-Key: fk_user_your_key"

curl https://api.fincept.in/user/transactions \
  -H "X-API-Key: fk_user_your_key"

{
  "success": true,
  "data": {
    "transactions": [
      {
        "id": 123,
        "transaction_id": "txn_abc123",
        "amount_inr": 4.99,
        "credits_purchased": 500,
        "status": "completed",
        "created_at": "2024-01-15T10:30:00Z",
        "completed_at": "2024-01-15T10:30:15Z"
      }
    ]
  }
}

# Free - Check if date is business day
/quantlib/core/date/is-business-day

# Free - Parse date from string
/quantlib/core/date/parse

# Free - Create schedule
/quantlib/scheduling/schedule

# Use Basic tier for simple statistics (1 credit)
/quantlib/statistics/mean

# Not Pro tier VaR (5 credits) for simple mean calculation

curl https://api.fincept.in/user/usage \
  -H "X-API-Key: fk_user_your_key"

X-RateLimit-Limit: 500
X-RateLimit-Remaining: 498
X-RateLimit-Reset: 1640998800

curl https://api.fincept.in/cashfree/plans \
  -H "X-API-Key: fk_user_your_key"

{
  "success": true,
  "data": {
    "plans": [
      {
        "plan_id": "basic_monthly",
        "name": "Basic Plan",
        "credits_amount": 500,
        "amount_inr": 499,
        "validity_days": 30,
        "description": "Perfect for individuals and small projects"
      }
    ]
  }
}