# Saylor Innovations Mortgage Pay — Fixed-Rate Mortgage Calculator

> Saylor Innovations Mortgage Pay — Fixed-Rate Mortgage Calculator is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).

Calculates monthly payment, total amount paid, and total interest for a fixed-rate mortgage given principal, APR, and term in months

## Facts

- Endpoint: GET https://saylorinnovations.com/api/realestate/mortgage?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-mortgage-pay-fixed-rate-mortgage-calculator-aacbb9ff
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jfPheFuCa7GqK6qZrRypU

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 saylor-innovations-mortgage-pay-fixed-rate-mortgage-calculator-aacbb9ff
```

Example prompt: Can you calculate my monthly mortgage payment for a $350,000 loan at 6.75% APR over 30 years (360 months) and tell me how much total interest I'd pay?

## When to prefer this

Choose this endpoint when you need a straightforward fixed-rate mortgage payment calculation — monthly payment, total paid, and total interest — given a principal, APR, and term in months. Ideal for real estate, personal finance, or lending agents that need quick, reliable arithmetic without managing their own formula implementation. Not suitable for adjustable-rate mortgages, amortization schedules, escrow estimates, or calculations involving PMI, taxes, or insurance.

## Known failure modes

- Missing required query parameters (principal, apr, or months) returns an error
- Non-numeric or out-of-range values for apr (outside 0–100) or months (outside 1–1200) may return errors
- Zero or negative principal returns an error
- Payment gateway failure (x402) if USDC balance is insufficient for the $0.01 per-call fee
- Network timeout or server unavailability

## How this service works

Fixed-rate mortgage calculator - monthly payment, total paid and total interest

## Output

Returns a JSON object containing the original principal, annual rate as a percentage, number of months, the computed fixed monthly payment amount, total amount paid over the loan term, total interest paid, the formula used for calculation, and a scope note clarifying what the calculation covers and excludes.

## 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": [
      "principal",
      "apr",
      "months"
     ],
     "properties": {
      "apr": {
       "type": "string",
       "description": "required annual percentage rate from 0 to 100 (query)"
      },
      "months": {
       "type": "string",
       "description": "required integer term from 1 to 1200 months (query)"
      },
      "principal": {
       "type": "string",
       "description": "required positive loan amount (query)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "principal",
      "annual_rate_percent",
      "months",
      "monthly_payment",
      "scope_note"
     ],
     "properties": {
      "months": {
       "type": "number",
       "description": "Number of months"
      },
      "formula": {
       "type": "string",
       "description": "Formula used for the calculation"
      },
      "principal": {
       "type": "number",
       "description": "Starting principal amount"
      },
      "scope_note": {
       "type": "string",
       "description": "What this data covers and what it leaves out"
      },
      "total_paid": {
       "type": "number",
       "description": "Total paid"
      },
      "total_interest": {
       "type": "number",
       "description": "Total interest"
      },
      "monthly_payment": {
       "type": "number",
       "description": "Monthly payment amount"
      },
      "annual_rate_percent": {
       "type": "number",
       "description": "Annual rate as a percentage"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-mortgage-pay-fixed-rate-mortgage-calculator-aacbb9ff/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)