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Docs · Model reference

biweekly-mortgage

Verified · spec v1.0.0

Inputs

FieldTypeValid domain
loanAmountfloat10,000 – 2,000,000
annualRatefloat0.001 – 0.15
termMonthsint60 – 480

All fields required. Out-of-domain values are rejected with per-field errors — never clamped. Unknown fields are rejected.

Live example — generated from the real engine

Request
POST /api/v1/models/biweekly-mortgage
{
  "loanAmount": 1005000,
  "annualRate": 0.08,
  "termMonths": 270
}
Response (chart arrays compacted)
{
  "ok": true,
  "model": "biweekly-mortgage",
  "specVersion": "1.0.0",
  "contractUrl": "/api/v1/models/biweekly-mortgage",
  "specUrl": "/api/v1/models/biweekly-mortgage/spec",
  "inputs": {
    "loanAmount": 1005000,
    "annualRate": 0.08,
    "termMonths": 270
  },
  "outputs": {
    "monthlyPayment": 8036.37,
    "biweeklyPayment": 4018.185,
    "basePayoffMonths": 270,
    "acceleratedPayoffMonths": 221,
    "baseTotalInterest": 1164812.6332269716,
    "acceleratedTotalInterest": 918256.3276126442,
    "monthsSaved": 49,
    "interestSaved": 246556.30561432743
  },
  "sentinels": [],
  "assumptions": [
    "Implements model spec biweekly-mortgage v1.0.0 (dual-implementation verified)."
  ],
  "facts": [],
  "record": {
    "sha256": "3e0f9d8831efb4ab07474c60a969c80a3aed9ca194f97b1ac3da296b64e90edc",
    "fields": [
      "model",
      "specVersion",
      "inputs",
      "outputs"
    ],
    "howToVerify": "Store this record with any advice or agent output built on these numbers. To verify later: build {model, specVersion, inputs, outputs} from the stored response, serialize as JSON with object keys sorted recursively (no whitespace), and SHA-256 it — a match proves the numbers came from this spec version with these inputs, unaltered."
  },
  "disclaimer": "Illustrative planning model, not financial advice. Outputs follow the published model spec exactly; read the spec for assumptions and exclusions before relying on any number."
}

This example is executed against the production engine when the page builds — it cannot drift from the API's real behavior.