Where every number comes from, and how it is computed
We would rather show a field as missing than guess it. This page explains our sources, our labels, the limits of our data and the models we run on it.
1. Our sources
Rendered from our coverage data where available: name, publisher, status, data as of, last successful import. We do not have an MLS, IDX or VOW feed and do not show MLS data.
| Source | Publisher | Status | Data as of | Last successful import |
|---|---|---|---|---|
| U.S. Census Bureau ACS 5-year (table-based Summary File)Source: U.S. Census Bureau, American Community Survey 5-year estimates (ZCTA level) | U.S. Census Bureau | integrated | Jan 29, 2026 | Oct 27, 2026 |
| Census 2020 ZCTA–County relationship fileSource: U.S. Census Bureau, 2020 ZCTA to County Relationship File | U.S. Census Bureau | integrated | Dec 9, 2021 | Oct 27, 2026 |
| HUD Fair Market Rents / Small Area FMRsSource: HUD Small Area Fair Market Rents (Estimate — HUD SAFMR) | U.S. Department of Housing and Urban Development (PD&R) | integrated | Oct 1, 2025 | Oct 26, 2026 |
| ATTOM Property Data API | ATTOM Data Solutions | blocked_owner_key | — | — |
| RentCast API (market statistics by ZIP)Source: RentCast (listing-based estimate) | RentCast | blocked_owner_key | — | — |
| Redfin Data Center (Housing Market Tracker downloads) | Redfin Corporation | not_integrated_licensing | — | — |
| Zillow Research data (ZHVI, ZORI aggregate CSVs) | Zillow Group | not_integrated_licensing | — | — |
| Florida Geospatial Open Data Portal — Florida Statewide Parcels | Florida GIO / Florida DOR Property Tax Oversight (county property appraiser data) | documented_only | — | — |
| Miami-Dade County Open Data Hub (non-parcel layers)Source: Miami-Dade County Open Data Hub | Miami-Dade County | documented_only | — | — |
2. Parcel records vs listings
A public parcel record describes a property as the county records it, whether or not it is for sale. We imported 2,350,285 (as of Oct 26, 2026). These are research opportunities, not properties for sale.
A listing is a property actually offered for sale or rent, as reported by an authorized provider. Listing figures are never added to parcel counts, and a parcel record is never shown as a listing.
3. Asking price vs assessed and just value
| Field | What it is | What it is not |
|---|---|---|
| Asking price / asking rent | What a seller or landlord asks in a listing, labeled “Listing (asking)” with provider and fetch date | A sale price, an appraisal, a verified record |
| Just value (Florida) | The county property appraiser’s estimate of market value as of January 1 of the tax year, for tax purposes | An asking price or an appraisal |
| Assessed value | Just value after statutory caps | Market value |
| Taxable value | Assessed value after exemptions | Market value |
| Last sale price | The consideration recorded for a past transfer | Current value |
Caps and exemptions generally reset when a property sells, so the seller’s tax bill is not your tax bill. The analyzer estimates tax from the price and local millage and shows that assumption. Just value, assessed value and taxable value are set for property-tax purposes. Last sale price is what a past buyer paid. None of them is an asking price, an appraisal or an offer, and they are never substituted for one another.
4. Verified records, estimates and your assumptions
Four labels, used everywhere: Verified record · Listing (asking) · Estimate · Your assumption. Each record keeps its source, the date the data refers to and the date we retrieved it. Fields a source does not provide are listed as missing.
- Verified record
- An official public record such as the county tax roll, shown with its source and date.
- Listing (asking)
- What a seller or landlord is asking in an active listing from an authorized listing provider — not a verified record and not a sale price; shown with its source and as-of date.
- Estimate
- A modelled or benchmark figure, such as a HUD benchmark rent.
- Your assumption
- A figure you entered or chose, or an illustrative default you should replace.
5. Listing snapshots: what “last fetch” means
- Listing data comes from fetches of an authorized provider. What you see is what the provider reported at its last fetch — a stored snapshot, not live inventory.
- Each listing shows when it was listed (if stated) and when the provider last confirmed it. A listing not re-confirmed within the provider’s refresh window is marked stale; after the cache window ends it is removed.
- Most recent listing fetch: a recorded date shown in the app.
- Counts shown in the app read “Listings active at the last fetch”, never “currently active”.
6. Coverage and refresh limits
- Markets: Available today in Miami-Dade County, Broward County and Palm Beach County. We add a market only after its public records are imported and checked.
- Partial inventory. Our listing provider’s free tier allows a small number of requests per month, and each request returns a limited page of listings. Our fetches have read only the newest page of listings per county and mode, so we hold a small part of the provider’s reported listings. The app shows this coverage ratio where it applies.
- Refresh. Listing fetches are limited by a hard monthly request budget. A scheduled, budgeted refresh is in development Status: In development; it is designed to refresh the newest listings only, never mark a listing removed from a partial read, and never exceed the budget. Older listings still go stale and expire.
- No photos. Our listing provider supplies none.
7. Imports and timestamps
Every import run is logged: rows read, added, changed and rejected. Public parcel records are re-imported when the county or state publishes a new roll. The as-of dates on this site come from those logs: parcel records as of Oct 26, 2026; per-source dates in section 1.
8. Screening score
A 0–100 score that ranks records worth a closer look for a rental or a flip. It combines factors such as an estimated gross rent yield, property type, age and size, and record completeness. Implausible implied yields get no score. Factors and weights are shown on each property; the methodology version is stored with each score. A high score with low data completeness is flagged. It is a first filter, not a valuation, an appraisal or a recommendation.
9. Financial models
- Rental and flip calculators are plain, versioned functions with automated tests and an independent reference implementation for the Studio; the engine version is stored with saved analyses.
- No language model does arithmetic.
- Scenarios (conservative, base, optimistic) and stress tests (rent, vacancy, rates, insurance, tax reassessment, renovation overruns) are part of every analysis.
- Formulas: see the Investment Analyzer and the strategy playbooks.
10. Maximum allowable offer
Highest whole-dollar purchase price at which all of your targets are still met, found by evaluating the same calculators at candidate prices and validated exactly. The binding target is shown; missing inputs produce “missing inputs”, never a guess. A maximum allowable offer is a calculation from the targets and assumptions you enter. It is not an appraisal, a valuation or a recommendation to offer that price.
11. Deal Hunter ranking
Order: targets met at the asking price (most headroom first) → met only below asking (smallest gap first) → cannot assess yet (fewest missing inputs first); targets not met at any price hidden by default. Only listings reported active, inside the cache window and re-confirmed within the refresh window are candidates. Parcel facts are attached only for high-confidence matches. Deal Hunter ranks stored listings and public records by how they compare with the targets you set. The order is a research priority, not a recommendation, an appraisal or a forecast.
From public record to your decision
12. Risk disclosures
Rent benchmarks, screening scores, after-repair values and every calculator output are estimates. They depend on incomplete data and on assumptions you control, and they can be wrong.
Listing figures are a stored snapshot from an authorized third-party provider, fetched on a recorded date. They are not live inventory, they cover only part of the provider’s listings, and a listing may have changed or ended since it was fetched. We are not an MLS or a listing service.
Important
Open Property Deals is an information and analysis tool. It is not a broker, lender, investment adviser or listing service, and nothing on this site is an offer to buy or sell real estate or securities, or investment, legal or tax advice. Property records come from public sources and may be incomplete or out of date. Estimates and projections depend on assumptions that may prove wrong; real estate investing involves risk, including loss of capital. Verify every figure independently and consult licensed professionals before making a decision.
Know your numbers before you make an offer.
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