Overview
Mortgage Calculator works by using the loan amount, interest rate, and loan term to calculate the monthly mortgage payment, total interest, and more.
Endpoint
One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.
curl -X POST https://api.apiverve.com/v1/mortgagecalculator \
-H "x-api-key: your_api_key_here" \
-H "Content-Type: application/json" \
-d '{
"amount": 570000,
"rate": 6.8,
"years": 30
}'const res = await fetch('https://api.apiverve.com/v1/mortgagecalculator', {
method: 'POST',
headers: {
'x-api-key': 'your_api_key_here',
'Content-Type': 'application/json',
},
body: JSON.stringify({
"amount": 570000,
"rate": 6.8,
"years": 30
}),
});
if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);
const { data } = await res.json();
console.log(data);import requests
res = requests.post(
"https://api.apiverve.com/v1/mortgagecalculator",
headers={"x-api-key": "your_api_key_here"},
json={
"amount": 570000,
"rate": 6.8,
"years": 30
},
timeout=15,
)
res.raise_for_status()
print(res.json()["data"])package main
import (
"fmt"
"io"
"net/http"
"strings"
)
func main() {
body := strings.NewReader(`{
"amount": 570000,
"rate": 6.8,
"years": 30
}`)
req, _ := http.NewRequest("POST", "https://api.apiverve.com/v1/mortgagecalculator", body)
req.Header.Set("Content-Type", "application/json")
req.Header.Set("x-api-key", "your_api_key_here")
res, err := http.DefaultClient.Do(req)
if err != nil {
panic(err)
}
defer res.Body.Close()
out, _ := io.ReadAll(res.Body)
fmt.Println(string(out))
}Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.
Authentication
Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.
A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.
Parameters
Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them.
| Parameter | Type | Description |
|---|---|---|
amountRequired | number | The loan amount range 0–∞ |
rateRequired | number | The interest rate (percentage) range 0–100 |
yearsRequired | integer | The loan term in years range 1–50 |
downpaymentOptional | number | The down payment amount range 0–∞ |
annual_propertytaxOptional | number | The annual property tax amount range 0–∞ |
annual_homeinsuranceOptional | number | The annual home insurance amount range 0–∞ |
annual_hoaOptional | number | The annual HOA amount range 0–∞ |
Response
Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.
{
"status": "ok",
"error": null,
"data": {
"amount": 570000,
"downpayment": 0,
"rate": 6.8,
"years": 30,
"total_interest_paid": 767750.49,
"total_loan_payment": 1337750.49,
"interestRatio": 57.39,
"monthly_payment": {
"total": 3715.97,
"mortgage": 3715.97,
"property_tax": 0,
"hoa": 0,
"home_insurance": 0
},
"annual_payment": {
"total": 44591.68,
"mortgage": 44591.68,
"property_tax": 0,
"hoa": 0,
"home_insurance": 0
},
"formatted": {
"amount": "$570,000",
"monthlyPayment": "$3,715.97",
"totalInterestPaid": "$767,750.49",
"totalLoanPayment": "$1,337,750.49"
},
"amortization_schedule": [
{
"month": 1,
"interest_payment": 3230,
"principal_payment": 485.97,
"remaining_balance": 569514.03
},
{
"month": 2,
"interest_payment": 3227.25,
"principal_payment": 488.73,
"remaining_balance": 569025.3
},
{
"month": 3,
"interest_payment": 3224.48,
"principal_payment": 491.5,
"remaining_balance": 568533.8
}
]
}
}Response fields
Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.
| Field | Type | Example | Description |
|---|---|---|---|
amount | number | 570000 | Loan amount in dollars |
downpayment | number | 0 | Down payment amount provided |
rate | number | 6.8 | Interest rate percentage used for calculation |
years | number | 30 | Loan term in years |
total_interest_paidPremium | number | 767750.49 | Total interest paid over entire loan term |
total_loan_paymentPremium | number | 1337750.49 | Total amount paid (principal + interest) |
interestRatioPremium | number | 57.39 | Percentage of payment that is interest |
monthly_payment | object | {...} | |
total | number | 3715.97 | Total monthly payment including all fees |
mortgage | number | 3715.97 | Monthly mortgage payment (principal + interest) |
property_tax | number | 0 | Monthly property tax portion of payment |
hoa | number | 0 | Monthly HOA fee portion of payment |
home_insurance | number | 0 | Monthly home insurance portion of payment |
annual_payment | object | {...} | |
total | number | 44591.68 | Total annual payment including all fees |
mortgage | number | 44591.68 | Annual mortgage payment (principal + interest) |
property_tax | number | 0 | Annual property tax portion of payment |
hoa | number | 0 | Annual HOA fee portion of payment |
home_insurance | number | 0 | Annual home insurance portion of payment |
formatted | object | {...} | |
amount | string | "$570,000" | Formatted loan amount with currency symbol |
monthlyPayment | string | "$3,715.97" | Formatted monthly payment with currency |
totalInterestPaid | string | "$767,750.49" | Formatted total interest paid with currency |
totalLoanPayment | string | "$1,337,750.49" | Formatted total loan payment with currency |
amortization_schedulePremium | array[3] | Month-by-month loan repayment schedule breakdown | |
monthPremium | number | 1 | Payment month number in loan term |
interest_paymentPremium | number | 3230 | Interest portion of monthly payment |
principal_paymentPremium | number | 485.97 | Principal portion of monthly payment |
remaining_balancePremium | number | 569514.03 | Outstanding loan balance after payment |
Errors
Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.
| Status | Meaning | What to do |
|---|---|---|
400 | Input was rejected | Read error; it names the parameter. |
401 | Key missing or invalid | Check the header name and the key value. |
403 | Key valid, but not permitted | A key restriction or IP allow-list; see key scoping. |
429 | Rate limited, or out of credits | Read error to tell them apart; see rate limits. |
Use cases
- Real Estate
- Calculate mortgage payments by using the Mortgage Calculator API. Use the data to estimate monthly payments and total interest for real estate transactions
- Financial Planning
- Plan financial budgets by using the Mortgage Calculator API to calculate mortgage payments. Use the data to manage expenses and savings
- Home Buying
- Estimate mortgage payments by using the Mortgage Calculator API. Use the data to determine affordability and budget for home purchases
- Loan Analysis
- Analyze loan terms by using the Mortgage Calculator API to calculate mortgage payments. Use the data to compare loan options and choose the best one
Other ways to use Mortgage Calculator
Set up Mortgage Calculator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.
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