⌂ Dashboard ↓ Download PDF
McKNIGHT MORTGAGEOS
McKnight MortgageOS
Complete User Guide & Manual
Everything you need to integrate, operate, and win with the platform — from your first sandbox key to production document OCR.
McKnight Prequal EngineGuideline Simulation EngineClosing Cost Intelligence Compliance TimingMortgage Lead IntelligenceMortgage Document Intelligence
Base URL
https://mcknight-mortgageos.pages.dev
Version
v1 · July 2026
Support
support@rjbusinesssolutions.org

Table of Contents

Important disclaimer, up front: The AUS engine performs guideline simulation modeled on published agency guidelines. It is not Desktop Underwriter® (DU®) or Loan Product Advisor® (LPA®) and does not return official findings. All outputs are decision-support estimates — final qualification is always determined by a licensed underwriter and official AUS submission.
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20262

01What Is McKnight MortgageOS?

Mortgage Intelligence is a mortgage decisioning API platform: six underwriting-grade engines behind one REST API, running on Cloudflare's global edge network. You send borrower data (or a photo of a paystub) — it returns qualification verdicts, affordability numbers, closing cost estimates, compliance dates, and lead scores in milliseconds.

Who it's for

You are…You use it to…
Loan officer / broker shopPre-qualify borrowers on the phone in real time; screen files before an official AUS run burns a credit pull.
Lender / credit unionEmbed instant prequal into your website; run guideline pre-checks across Conventional, FHA, VA, USDA, Jumbo simultaneously.
PropTech / FinTech builderPower "How much house can I afford?" features with real 2026 guideline math instead of nonsense calculators.
Lead aggregatorScore mortgage leads 0–100 on qualification likelihood before selling or routing them.

The six engines

Prequal
Multi-program qualification, DTI, 0–100 score, max home price, compensating factors
AUS Sim
DU + LPA-style dual verdicts with findings, modeled on published agency guidelines
Closing Costs
TRID-aligned Loan Estimate cost breakdown, all 50 states, cash-to-close
Compliance
LE/CD timing, 3-day waiting periods, mailbox rule, tolerance cure analysis
Leads
Capture + auto-score leads on qualification likelihood, pipeline API
Document OCR
Paystub/W-2/bank statement/1040/1099 → parsed fields → qualifying income → auto-prequal

Platform facts

<100ms typical engine response2026 loan limits verifiedAll 50 statesEdge-deployed (300+ cities)SHA-256 hashed keysNo SSN required

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20263

02Getting Started in 5 Minutes

Step 1 — Get your free sandbox key (no card, instant)

Visit mcknight-mortgageos.pages.dev/signup, or via API:

curl -X POST https://mcknight-mortgageos.pages.dev/api/v1/signup \
  -H "Content-Type: application/json" \
  -d '{"company_name": "Acme Lending", "email": "you@acmelending.com"}'

The response contains your API key once — store it securely. Sandbox includes 25 prequals, 5 AUS runs, and 10 document analyses per month, free forever.

Step 2 — Make your first pre-qualification call

curl -X POST https://mcknight-mortgageos.pages.dev/api/v1/prequal/submit \
  -H "Authorization: Bearer mga_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "first_name": "John", "last_name": "Doe",
    "income_sources": [{"income_type": "W2_SALARY", "monthly_amount": 8500}],
    "credit_profile": {"fico_score": 720},
    "debts": [{"debt_type": "auto", "monthly_payment": 450}],
    "down_payment": 60000, "liquid_assets": 45000,
    "property_state": "TX", "years_employed": 4
  }'

Step 3 — Read the verdict

{
  "qualification": { "status": "Strong - Excellent Approval Odds", "qualification_score": 100 },
  "affordability": { "max_home_price": 374791.27, "max_loan_amount": 314791.27 },
  "program_eligibility": [
    { "program": "Conventional", "eligible": true, "dti_back": 22.1 },
    { "program": "FHA", "eligible": true }, { "program": "VA", "eligible": false, "reason": "..." }
  ],
  "stored_id": "2d42e9c5-..."
}
That's it. You now have a qualification verdict, a max home price, and per-program eligibility — from one call. Every submission is stored to your account history (GET /api/v1/prequal/history).

Interactive dashboard

The homepage at mcknight-mortgageos.pages.dev is a live console: paste your key in the key field, then use the Prequal / AUS / Closing / Compliance / Leads / Usage tabs to fire real requests without writing code. The Docs tab lists every endpoint.

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20264

03Authentication, Plans & Quotas

Authentication

All engine endpoints require your API key as a Bearer token:

Authorization: Bearer mga_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Plans

PlanPricePrequals/moAUS/moDocs/moDaily callsOverages
Sandbox$0 forever25510250
Starter$299/mo · $2,990/yr500501001,000$0.75 prequal · $3 AUS
Professional$999/mo · $9,990/yr5,0005001,00010,000$0.40 prequal · $2 AUS
Enterprisefrom $2,500/moUnlimited + SLA, white-label, custom guidelinesContact us

Annual billing = 2 months free. Upgrade self-serve at /pricing (Stripe checkout, card charged immediately, account upgraded automatically within seconds via webhook — your existing key keeps working with new quotas). Enterprise: /contact.

Checking your usage

curl https://mcknight-mortgageos.pages.dev/api/v1/billing/usage \
  -H "Authorization: Bearer mga_live_YOUR_KEY"

{ "tier": "STARTER",
  "prequal":   { "quota": 500, "used": 112, "remaining": 388 },
  "aus":       { "quota": 50,  "used": 9,   "remaining": 41 },
  "documents": { "quota": 100, "used": 23,  "remaining": 77 } }

Quotas reset monthly on your billing date (paid plans — triggered by the paid invoice) . Exceeding a quota returns HTTP 403 QUOTA_EXCEEDED.

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20265

04McKnight Prequal Engine

POST/api/v1/prequal/submit

Request fields

FieldTypeNotes
first_name, last_namestring · requiredBorrower name
income_sources[]array · requiredEach: income_type (W2_SALARY, SELF_EMPLOYED, HOURLY, COMMISSION, BONUS, OVERTIME, RENTAL, PENSION, DISABILITY, ALIMONY…), monthly_amount, optional months_history
credit_profileobject · requiredfico_score (or per-bureau scores — middle score used), late payments, bankruptcies, foreclosures, collections
down_paymentnumber · requiredDollars available for down payment
debts[]arrayMonthly obligations; set will_be_paid_off: true to exclude
purchase_pricenumberOmit to solve for max affordability instead
property_state, occupancy, unitsPrimary / Second Home / Investment; 1–4 units
is_veteran, is_first_time_buyer, usda_eligible_area, high_cost_areabooleanUnlock VA / USDA / high-balance analysis
interest_ratenumberAssumed rate for affordability (defaults to current market assumption)

What you get back

2026 DTI & program limits used

ProgramFront DTIBack DTI (base/comp)Min FICOMax LTV
Conventional28%45% / 50%62097%
FHA31%43% / 50%58096.5%
VA41% / 60%580100%
USDA29%41% / 44%640100%
Jumbo28%38% / 43%70090%

Related: GET /prequal/history (last 50) · GET /limits + GET /limits/check?loan_amount=… (2026 conforming/FHA limits, public) · GET /programs

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20266

05Guideline Simulation Engine

POST/api/v1/aus/submit

What this is: a pre-check that simulates agency underwriting guidelines so you can catch problems before paying for an official DU®/LPA® run. What this is not: an official AUS. Findings are modeled, not GSE-issued.

Request shape

{
  "loan_number": "L-2026-0455",
  "systems": ["DU", "LP"],              // run one or both simulations
  "borrower": {
    "first_name": "Maria", "last_name": "Santos",
    "credit_score": 705, "monthly_income": 9200,
    "is_self_employed": false, "years_employed": 6
  },
  "property": {
    "state": "FL", "property_value": 450000,
    "occupancy_type": "PrimaryResidence", "units": 1
  },
  "loan_details": {
    "loan_amount": 405000, "loan_purpose": "Purchase",
    "loan_term_months": 360, "interest_rate": 6.5,
    "loan_type": "Conventional", "monthly_debts": 850
  }
}

Response highlights

Submissions persist: GET /aus/submissions lists them, GET /aus/submissions/:id/findings re-fetches full findings.

When to use AUS-sim vs Prequal

ScenarioUse
Borrower on the phone, exploring budgetPrequal — fast, program-wide, needs less data
File nearly complete, about to submit to DU/LPAAUS-sim — catch findings before the official run
Website affordability widgetPrequal
Pipeline triage: which files are submit-ready?AUS-sim in batch
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20267

06TRID Closing Cost Engine

POST/api/v1/closing-costs

Request shape

{
  "loan_amount": 320000, "property_value": 400000, "down_payment": 80000,
  "loan_type": "Conventional", "interest_rate": 6.625, "loan_term_months": 360,
  "state": "TX",
  "discount_points": 0.5, "seller_credit": 5000,
  "property_tax_annual": 7200, "homeowners_insurance_annual": 2100,
  "closing_date": "2026-09-15"
}

What it returns — Loan Estimate structure

SectionContents
A — OriginationOrigination fee, discount points, underwriting/processing
B — Cannot shopAppraisal, credit report, flood cert, MERS, tax service
C — Can shopTitle services, lender's title insurance, survey, settlement
E — Taxes & gov feesRecording + state-specific transfer taxes (all 50 states)
F — PrepaidsPer-diem interest to first payment, insurance year-1, MIP/VA funding fee where applicable
G — EscrowInitial escrow deposits (months of taxes + insurance)
Cash to closeDown payment + costs − credits, with program-specific items (FHA UFMIP, VA funding fee incl. disabled-vet exemption, USDA guarantee fee)

Every response includes estimated total closing costs, cash-to-close, and monthly payment (PITI + MI where LTV requires it).

Tip: pass is_veteran_disabled: true on VA loans to zero the funding fee — a commonly missed exemption worth thousands.
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20268

07Compliance Timing Tools

TRID timing violations are expensive. These endpoints compute legally significant dates using the federal-holiday-aware business day calendar.

EndpointWhat it answers
POST /compliance/le-timing"Given this application date, when must the Loan Estimate be delivered?" (3 business days) — plus earliest allowable closing
POST /compliance/cd-timing"Given this CD delivery date and method, when can we close?" (3-day waiting period; mailbox rule adds 3 days for non-hand delivery)
POST /compliance/tolerance"Fee changed between LE and CD — is it a violation and what's the cure?" Zero / 10% aggregate / unlimited tolerance buckets with exact cure amounts
GET /compliance/holidays/:yearFederal holiday calendar for any year
GET /compliance/business-days?start=…&days=…General-purpose TRID business-day calculator

Example — CD timing with mailbox rule

curl -X POST .../api/v1/compliance/cd-timing \
  -H "Authorization: Bearer mga_live_YOUR_KEY" -H "Content-Type: application/json" \
  -d '{"cd_delivery_date": "2026-09-08", "delivery_method": "mail"}'

{ "received_date": "2026-09-11",      // +3 days mailbox rule
  "earliest_closing_date": "2026-09-15",
  "waiting_period_days": 3, "notes": ["Mailbox rule applied…"] }

Example — tolerance cure

{ "category": "zero_tolerance", "violation": true,
  "cure_amount": 150.00,
  "explanation": "Lender fees are zero-tolerance; any increase over LE requires a cure." }
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 20269

08Lead Capture & Scoring

Capture consumer mortgage leads and score them 0–100 on qualification likelihood — so your team calls the winners first (or you price lead inventory correctly).

EndpointPurpose
POST /leadsCreate + auto-score a lead (persists to your pipeline)
GET /leadsYour pipeline, sorted by score descending
POST /leads/scoreScore without persisting (e.g., real-time bid decisions)

Scoring inputs

Credit band, income vs. target price, down payment strength, employment stability, timeline urgency, and property/occupancy type feed a weighted 0–100 score with a hot/warm/cold classification.

curl -X POST .../api/v1/leads -H "Authorization: Bearer mga_live_YOUR_KEY" \
  -H "Content-Type: application/json" -d '{
  "first_name": "Dana", "last_name": "Fields", "email": "dana@example.com",
  "credit_range": "700-749", "annual_income": 110000,
  "down_payment_saved": 40000, "target_price": 380000,
  "timeline": "0-3 months", "employment_type": "W2"
}'
→ { "lead_id": "…", "score": 84, "classification": "hot", "factors": [...] }
Workflow idea: pipe your web form → POST /leads → route score ≥75 to senior LOs, 50–74 to nurture campaigns, <50 to automated drip. The score factors explain every number, so LOs know the angle before dialing.
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202610

09Mortgage Document Intelligence (OCR)

POST/api/v1/documents/analyze

Upload a borrower document photo — get back the document type, every extracted field, a computed qualifying monthly income per standard agency methods, and (optionally) a full pre-qualification in the same call.

Supported documents & extracted fields

DocumentFields extractedIncome method
PaystubPay period, frequency, gross current/YTD, net, hours, rate, OT/bonus/commission YTDCurrent gross × frequency factor, YTD cross-check (conservative lower figure), OT/bonus flagged for 2-yr average
W-2Box 1/3/5 wages, withholding, year, EIN, stateBox 1 ÷ 12 (2-yr averaging note)
Bank statementBalances, deposits, withdrawals, NSF countAsset verification (not income for agency loans)
1040 returnLine 9/11, Schedule C net profit, wagesSch C ÷ 12 for self-employed (add-back note)
1099Variant, payer, amount, yearAnnual ÷ 12 (2-yr history note)

Upload formats

The killer feature — document → instant prequal

curl -X POST .../api/v1/documents/analyze \
  -H "Authorization: Bearer mga_live_YOUR_KEY" \
  -F "file=@paystub.png" \
  -F "auto_prequal=true" \
  -F 'borrower={"credit_profile":{"fico_score":720},"down_payment":60000,
       "property_state":"NM","debts":[{"debt_type":"auto","monthly_payment":450}]}'

→ doc_type: PAYSTUB · qualifying income: $8,910.30/mo
→ auto_prequal: score 100 · max home price: $374,791 · stored in history

Credit score and down payment must come from you — documents can't establish them. The derived income becomes a W2_SALARY (or SELF_EMPLOYED) income source automatically.

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202611

09Mortgage Document Intelligence — continued

Managing analyzed documents

EndpointPurpose
GET /documents/historyYour last 50 analyses with doc type, confidence, derived income
GET /documents/:idFull record: all fields, income analysis, OCR stats
DELETE /documents/:idPermanently deletes the analysis AND the stored file — use for privacy compliance / borrower deletion requests

Accuracy & trust model

PII rules for document upload: obtain the borrower's consent before uploading; redact SSNs and full account numbers where practical. Files are stored encrypted at rest in private object storage, are never used for model training, and are deletable on demand. See /privacy §3.

Best-practice image checklist

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202612

10Billing, Upgrades & Usage

Upgrading from Sandbox

  1. Go to /pricing → click Subscribe on Starter or Professional
  2. Enter your email (use the same email as your sandbox signup to upgrade in place — your existing API key keeps working with the new quotas)
  3. Choose monthly or annual (2 months free) → pay via Stripe's secure checkout
  4. Within seconds the webhook provisions your account. New customers see their API key once on the success page — copy it immediately

Billing lifecycle

EventWhat happens automatically
Subscription renews (invoice paid)Account re-activated if needed; monthly usage counters reset to 0
Payment failsAccount suspended (API returns auth errors) until payment succeeds
Subscription cancelledAccount closed at period end

To cancel or change plans, email support@rjbusinesssolutions.org (self-serve portal coming). Annual plans are non-refundable except where law requires.

API key management

# Generate an additional production key (returned once)
curl -X POST .../api/v1/keys -H "Authorization: Bearer mga_live_EXISTING_KEY" \
  -H "Content-Type: application/json" -d '{"key_name": "Production Server 2"}'
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202613

11Errors, Limits & Troubleshooting

Error format

{ "error": { "code": "QUOTA_EXCEEDED", "message": "Monthly PREQUAL quota exceeded (500/500)…", "details": {…} } }

Error reference

HTTPCodeMeaning / fix
401UNAUTHORIZEDMissing/invalid key. Check the Authorization: Bearer header.
401DEMO_KEY_DISABLEDDemo keys don't work in production — get a free key at /signup.
403QUOTA_EXCEEDEDMonthly quota hit. Upgrade at /pricing or wait for reset.
400INVALID_REQUESTMissing required fields — message lists them.
409ALREADY_REGISTEREDSignup email already has an account.
413FILE_TOO_LARGEDocument over 4MB — compress or downscale.
415UNSUPPORTED_TYPEOnly JPEG/PNG/WebP. Convert PDFs to PNG first.
502OCR_FAILEDImage unreadable. Retake per the checklist in §09. No quota consumed.

Integration best practices

Getting help

Email support@rjbusinesssolutions.org with your client_id (never your API key), the endpoint, timestamp, and the full error body. Starter: 48h response · Professional: 12h priority · Enterprise: dedicated Slack.

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202614

12Compliance & Legal Notes

The disclaimer that governs everything: This platform provides guideline simulation and estimation for decision-support purposes. It is not Desktop Underwriter® (Fannie Mae), Loan Product Advisor® (Freddie Mac), or any official automated underwriting system, and returns no official findings. Final qualification, pricing, and approval are always determined by a licensed lender, official AUS submission, and full underwriting. DU® and LPA® are registered trademarks of their respective owners; no affiliation or endorsement is implied.

Your responsibilities as an API customer

What we do on our side

Full terms: mcknight-mortgageos.pages.dev/terms · Privacy: /privacy · Governing law: New Mexico, USA.

McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202615

AAppendix: Complete Endpoint Reference

EndpointAuthPurpose
POST/api/v1/signupFree sandbox account + instant key
POST/api/v1/contactDemo / enterprise / partnership request
GET/api/v1/limits · /limits/check · /programs2026 loan limits & program catalog
GET/healthLiveness + DB status
POST/api/v1/prequal/submit🔑Multi-program pre-qualification
GET/api/v1/prequal/history🔑Last 50 prequals
POST/api/v1/aus/submit🔑DU/LPA-style guideline simulation
GET/api/v1/aus/submissions · /:id/findings🔑Submission history + findings
POST/api/v1/closing-costs🔑TRID LE-style cost estimate
POST/api/v1/compliance/le-timing · /cd-timing · /tolerance🔑TRID timing & tolerance
GET/api/v1/compliance/holidays/:yr · /business-days🔑Calendars
POST/api/v1/leads · /leads/score🔑Lead capture + scoring
GET/api/v1/leads🔑Scored pipeline
POST/api/v1/documents/analyze🔑OCR + parse + income + optional auto-prequal
GET/api/v1/documents/history · /:id🔑Analysis records
DEL/api/v1/documents/:id🔑Delete analysis + file
GET/api/v1/billing/usage🔑Quotas + usage
POST/api/v1/keys🔑Additional API key
POST/api/v1/billing/checkoutStripe subscription checkout

Web pages

/ interactive console · /pricing plans + subscribe · /signup free key · /contact demo · /manual this guide · /terms · /privacy · /brand brand kit

Base URL for every call: https://mcknight-mortgageos.pages.dev — engines respond in <100ms from 300+ edge locations worldwide.
McKnight MortgageOS — User Guide & ManualMcKnight Opportunity Group · July 202616