Mortgage affordability (28/36 DTI) API

Max home price from the 28/36 DTI rule: housing payment ≤ min(28%·grossMonthly, 36%·grossMonthly − otherDebts), inverted through the amortization formula to a max loan, plus the binding constraint. Answers 'how much house can I afford on 120k', 'what's my max loan at 6.5%', 'which ratio is limiting me — front or back end'.

Price$0.01per request

MethodPOST

Route/v1/calc/re-mortgage-affordability

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

real-estateaffordabilitydtimortgageincomeratiofinancecalc

API URLhttps://x402.hexl.dev/v1/calc/re-mortgage-affordability

Integration docs

Example request

{
  "grossAnnualIncome": 120000,
  "monthlyDebts": 500,
  "annualRatePct": 6.5,
  "termYears": 30,
  "downPayment": 60000
}

Example response

{
  "maxMonthlyHousingPayment": 2800,
  "maxLoanAmount": 442990.29,
  "maxHomePrice": 502990.29,
  "bindingConstraint": "front-end (housing ratio)",
  "frontEndCap": 2800,
  "backEndCap": 3100,
  "frontEndPct": 28,
  "backEndPct": 36
}

Input schema

{
  "type": "object",
  "required": [
    "grossAnnualIncome",
    "annualRatePct",
    "termYears"
  ],
  "properties": {
    "grossAnnualIncome": {
      "type": "number",
      "examples": [
        120000
      ]
    },
    "monthlyDebts": {
      "type": "number",
      "description": "other monthly debt payments",
      "examples": [
        500
      ]
    },
    "annualRatePct": {
      "type": "number",
      "examples": [
        6.5
      ]
    },
    "termYears": {
      "type": "number",
      "examples": [
        30
      ]
    },
    "downPayment": {
      "type": "number",
      "examples": [
        60000
      ]
    },
    "frontEndPct": {
      "type": "number",
      "default": 28
    },
    "backEndPct": {
      "type": "number",
      "default": 36
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}