Monthly Payment API

How it works

1. On page load, call GET /v1/{brand}/options to get the two customer questions (labels + dropdown values).
2. With the customer’s answers plus the structure’s delivery ZIP and total price, call POST /v1/{brand}/estimate.
3. Show what comes back. Eligibility, terms, payments, APRs, Apply links and disclosure text are all pre-computed.

Your widget, your layout

You decide when to call the API and how to show the results. No button is required. The test page lets you try three styles:

• A · Automatic: call /estimate whenever an input or the price changes, and show the payments without a button.
• B · Term dropdown: show one payment and let the customer switch terms from a dropdown (start on loans.defaultTermYears).
• C · Button + tiles: the customer presses a button, then picks a term tile.

For automatic updates, only call the API once the ZIP has 5 digits, price is above 0 and both questions are answered. Wait about 0.4 seconds after the last keystroke, and ignore any older response that comes back after a newer one. That keeps it fast and well under the limit of 120 rent-to-own quotes per visitor every 10 minutes. Switching terms needs no new call, because every term is already in the response.

Try A · Try B · Try C

1 · GET /v1/stoltzfus/options

Build your two <select>s from questions.creditScore.options and questions.ownProperty.options, then send the value back.

{
  "questions": {
    "creditScore": { "label": "What is your credit score?", "placeholder": "— Select credit score —",
      "options": [ { "value": "840", "label": "840 – 850" }, … { "value": "500", "label": "Below 550" } ] },
    "ownProperty": { "label": "Do you own the property where the project is located?",
      "options": [ { "value": "own", "label": "Yes, I own the property" },
                   { "value": "biz", "label": "Yes, my business owns the property" },
                   { "value": "no",  "label": "No, I do not own the property" } ] }
  },
  "lenders": { "upgrade": { "minCreditScore": 680, "minAmount": 2000, "maxAmount": 100000, … }, "thrive": { … }, "rto": { … } },
  "disclosures": { … }, "displayRules": [ … ]
}

2 · POST /v1/stoltzfus/estimate

GET /v1/stoltzfus/estimate?zip=19310&price=16820&creditScore=720&ownProperty=own also works, which is handy for testing in a browser tab.

const res = await fetch('https://payment-estimate-api.pages.dev/v1/stoltzfus/estimate', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ zip: '19310', price: 16820, creditScore: '720', ownProperty: 'own' })
});
if (res.status === 503) { /* hide the payment section — estimates temporarily off */ }
const data = await res.json();

Response (shortened)

{
  "ok": true,
  "input": { "zip": "19310", "state": "PA", "price": 16820, "creditScore": "720", "ownProperty": "own" },
  "loans": {
    "available": true,
    "defaultTermYears": 20,                     // pre-select this term (the longest)
    "terms": [                                  // ONE payment per term — use these for your payment choices
      { "years": 5, "label": "5-Year", "monthlyPaymentDisplay": "$372", "aprDisplay": "7.99% APR*", "footnote": "†",
        "paymentNote": "Months 1–6 are interest-only; …", "bestLender": "thrive",
        "offers": [ { "lenderName": "Thrive Financial", "monthlyPaymentDisplay": "$372", "aprDisplay": "7.99% APR*", "applyUrl": "…" },
                    { "lenderName": "Upgrade", "monthlyPaymentDisplay": "$349", "aprDisplay": "8.99% APR*", "applyUrl": "…" } ] },
      …
      { "years": 20, "label": "20-Year", "monthlyPaymentDisplay": "$164", "aprDisplay": "9.99% APR*", "footnote": "†", "offers": [ … Thrive only … ] }
    ],
    "byLender": {                               // full per-lender detail, exactly as the estimator shows it
      "upgrade": { "eligible": true, "terms": [ 5, 7, 10, 12, 15-year … ] },
      "thrive":  { "eligible": true, "terms": [ … incl. interestOnlyPayments for months 1–6 … ] }
    },
    "message": null                             // text to show when available = false
  },
  "rentToOwn": {
    "available": true, "creditCheck": false, "defaultTermMonths": 48,
    "terms": [ { "months": 24, "monthlyPaymentDisplay": "$1,048.77", "upfrontPayment": 3364 }, … ],
    "overMaxText": null,                        // set when the price is over $25,000 (payments are for $25,000)
    "notes": [ "Rent-to-own is not available for 2-story structures or …" ],
    "applyUrl": "https://www.smartpayrentals.com/app/StoltzfusStructures",
    "reason": null, "reasonText": null          // why it’s unavailable, when available = false
  },
  "disclosures": {
    "forThisWidget": [                          // show ALL of these, in order — word-for-word from our estimator
      { "type": "paragraph", "paragraphs": [ { "text": "Stoltzfus Structures is not a lender…", "html": "…" } ] },
      { "type": "heading", "text": "Important Disclosures" },
      { "type": "section", "id": "disc-rto", "title": "Rent-to-Own (SmartPay)",
        "paragraphs": [ { "text": "You do not own the structure until…", "html": "… higher than the cash price …" } ] },
      …
    ],
    "all": [ … ],                               // the estimator's whole footer, incl. products this widget doesn't offer
    "representativeExample": "…", "rentToOwnStructures": "Structures that are 2 stories or … do not qualify for rent-to-own."
  },
  "displayRules": [ … ]
}

Errors return HTTP 400 with {"ok":false,"error":"invalid_input","fields":{"zip":"Enter a 5-digit US ZIP code"}}. The messages are written for customers, so you can show them as-is.

Display rules (please follow)

• Always show a loan payment together with its APR and term. Never show a payment by itself.
• Keep the * on APRs and the † on interest-only terms, and put the matching disclosures on the page.
• Don’t name the lender on the payment choices. Show lender names only at the Apply step (terms[].offers).
• No APR or interest rate for rent-to-own. It’s a lease, not a loan.
• When a result has overMaxText, show it next to those payments.
• Disclosures: render every block in disclosures.forThisWidget, in order. Use html to keep the bold text. They are copied word-for-word from our estimator and update automatically when we change them, so please don’t retype or edit them.
• Show each lender’s applyHint (the small print under our Apply buttons) next to its Apply button.
• Don’t call any of these products “unsecured”.

Questions

Tim Brazil, Lending Manager. Rates and rules are maintained on our side. When a lender changes terms, our estimator is updated, and this API and your widget pick up the change automatically.