# SiteCheck Finance Loan Calculator

> SiteCheck Finance Loan Calculator is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-16).

Computes loan amortization schedules, compound growth, NPV, and IRR using pure financial math — returning a full month-by-month breakdown of payments, interest, and balance.

## Facts

- Endpoint: GET https://api.sitecheck-api.workers.dev/api/finance/loan?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-finance-loan-calculator-5ee3fb22
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DQqegzeoiW68O1INXseI9

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability sitecheck-finance-loan-calculator-5ee3fb22
```

Example prompt: Can you calculate the monthly payment and full amortization schedule for a $250,000 annuity loan at 6.5% annual interest over 30 years?

## When to prefer this

Choose this endpoint when you need server-side loan amortization, compound interest projection, NPV, or IRR computation without implementing the math yourself. It is ideal for agents embedded in financial planning, mortgage advisory, or investment analysis workflows. It runs pure-code computation (no external data source) making results reproducible and deterministic. At $0.001 per call it is extremely cost-effective for on-demand financial calculations.

## Known failure modes

- Missing required 'mode' parameter returns an error
- Invalid or out-of-range rate (e.g. negative or over 100 for annuity) causes a validation error
- Conflicting termYears and termMonths parameters may cause unexpected behavior
- Cashflows parameter missing for NPV or IRR mode
- Principal missing for annuity mode
- Term exceeding 50 years or 600 months rejected

## How this service works

Loan and investment calculator in exact cents, no outside source. mode=annuity: monthly payment, total interest and the full amortisation schedule (up to 600 months). mode=compound: future value of an initial sum plus monthly contributions. mode=npv or irr: discount or internal rate of return of a list of cashflows (up to 200, the first at time 0). Rates are percentages from 0 to 100 a year (per period for npv and irr); terms up to 50 years.

## Output

A JSON object containing the calculation mode, interest rate, number of months, monthly payment amount, last payment (may differ slightly due to rounding), total paid, total interest, a full month-by-month schedule (each entry with month number, remaining balance, payment, interest portion, and principal portion), a source note confirming pure-code computation, a disclaimer, and a checkedAt timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "mode"
     ],
     "properties": {
      "mode": {
       "type": "string",
       "description": "annuity (default), compound, npv or irr"
      },
      "rate": {
       "type": "string",
       "description": "Annual rate in percent, 0 to 100 (annuity, compound); rate per period in percent for npv (-99 to 1000)"
      },
      "cashflows": {
       "type": "string",
       "description": "Comma-separated cashflows for npv and irr, e.g. -1000,300,400,500 (first at time 0)"
      },
      "principal": {
       "type": "string",
       "description": "Loan amount (annuity) or starting sum (compound), up to two decimals (optional for compound)"
      },
      "termYears": {
       "type": "string",
       "description": "Term in years, up to 50 (annuity, compound)"
      },
      "termMonths": {
       "type": "string",
       "description": "Term in months, 1 to 600, instead of termYears"
      },
      "contribution": {
       "type": "string",
       "description": "Monthly contribution for compound, up to two decimals (optional)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mode": "annuity",
  "rate": 6.5,
  "months": 360,
  "source": "Computed here in pure code (annuity, monthly compounding, NPV and IRR formulas); no outside source",
  "schedule": [
   {
    "month": 1,
    "balance": 249774,
    "payment": 1580.17,
    "interest": 1354.17,
    "principal": 226
   },
   {
    "month": 2,
    "balance": 249546.77,
    "payment": 1580.17,
    "interest": 1352.94,
    "principal": 227.23
   },
   {
    "month": 3,
    "balance": 249318.31,
    "payment": 1580.17,
    "interest": 1351.71,
    "principal": 228.46
   }
  ],
  "checkedAt": "2026-10-15T13:40:01.487Z",
  "principal": 250000,
  "totalPaid": 568861.58,
  "disclaimer": "Information only, not financial advice.",
  "lastPayment": 1580.55,
  "totalInterest": 318861.58,
  "monthlyPayment": 1580.17
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sitecheck-finance-loan-calculator-5ee3fb22/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.sitecheck-api.workers.dev](https://www.zero.xyz/host/api.sitecheck-api.workers.dev/llms.txt)