Fairness check for one Maryland property assessment against genuinely similar homes (same triennial reassessment group, similar size, lot and age, same zip), from a copy of the state's own assessment roll (SDAT) refreshed monthly. Input is a Maryland street address with its zip, its Maryland city or county, or MD, or an SDAT account id (acct); the city, county, state and zip can be written in the address itself (1 STATE CIR, ANNAPOLIS, MD 21401), a city or county narrows the match to that place the way a zip does, and MD alone matches the street across the whole state. A single match returns the parcel record, a uniformity object, a plain-language verdict, Maryland's appeal windows with official filing links, and honesty notes. In the parcel record, market_value is the full value an appeal argues about; taxable_now is the phased-in assessment for the Maryland tax year holding today (tax years run July 1 to June 30; taxable_now_tax_year gives its from and to dates, YYYY-MM-DD), and taxable_next with taxable_next_tax_year is the one for the tax year after; either pair is left out when the roll does not hold that year. The uniformity object gives BandSize (how many similar homes), where the assessment sits among them as percentiles (PctFMV for market value, PctImprPSF for improvement value per square foot, PctLand for land value), their medians (MedianFMV, MedianImprPSF, MedianLand), the median sales ratio of assessment to sale price (MedianSalesRatio) and its coefficient of dispersion (COD) over RatioSales sales dated RatioFromYear through RatioToYear (three calendar years ending with the year of the roll's newest sale dated on or before today), and Branch. RatioSales counts sales of $100,000 or more that the roll codes as arm's-length sales of one improved parcel; foreclosures, gifts, auctions, sales of several parcels for one price and sales of a vacant lot are left out. When the roll records no lot size or no year built for the home, the band skips that test: NotCompared names it (lot size or year built; both as lot size, year built) and the plain verdict's not_compared field says so in words. NotCompared is absent when every test ran. When the assessment sits high (PctFMV 75 or more) or low (below 25) and the home's rank on total value per square foot sits 3 or more in 10 from its rank on total value, the plain verdict's size field says so: total value is the rate per square foot times living area, so the difference comes from the home's size. Verdict branches: fair means the assessment is below the 75th percentile of similar homes (the plain headline calls it on the low side below the 25th and lower than almost all of them below the 10th, and the normal range otherwise); review means it is on the high side; elevated means it is higher than almost all of them; insufficient means fewer than 25 similar homes exist for a fair comparison, which is no finding either way. On the insufficient branch the percentile and median fields are 0, meaning not computed. A single-match or multiple_matches result also carries a roll object: as_of is the date the state last updated the roll and pulled is the date this copy was taken (both YYYY-MM-DD), overdue is true when this copy is more than 35 days old, and a field the server does not know is left out. MedianSalesRatio and COD are 0 when RatioSales is below 10, meaning no ratio is published. When several parcels share the address, the result is multiple_matches, listing parcels with their account ids; passing one of those ids as acct selects that parcel. The list is in unit order, each option carries unit (the unit as the roll writes it, such as UNIT 204) when the roll records one, and total gives how many parcels share the address; when more than 10 do (a condominium building, for instance), the list holds the first 10. A unit written after the street (100 HARBORVIEW DR UNIT 204, 100 HARBORVIEW DR #204, or as its own comma-separated part) narrows the match to that unit when the roll records units at the address, and a single match then carries parcel.unit; when the roll records units there and none is the unit written, the result is an error naming that unit, with no match list; a unit at an address where the roll records none is not applied. Every refusal and every miss below is a tool error: isError is true and the text content is the error message, with no verdict and no match list. When nothing matches, the result is an error; the roll writes addresses in its own form (e.g. 1 STATE CIR), so a miss can mean a different spelling, a town other than the one the roll records, or a zip other than the one the roll records, rather than a missing parcel. A zip is 5 digits; a ZIP+4 (21202-1234) is read as its first five digits, and a zip in the zip input takes precedence over one written in the address. A malformed zip or acct returns an error naming the expected form, a zip outside Maryland returns an error stating that only Maryland is covered, an address naming another state or territory returns an error stating that only Maryland is covered and naming that state as not covered yet, an address with no Maryland zip, city, county or state returns an error stating that only Maryland is covered and that a zip, city or county is needed, and an acct the roll does not hold returns an error stating that no parcel has that account id; none of these carries a verdict or a match list. Without a Maryland zip or MD, an address also gets the error asking for a zip, city or county when a comma-separated part after the street is not read as a Maryland place, a state, a zip, a unit or the US, such as a town Maryland lacks, another country or a state written as Miss. (100 MAIN ST, DOVER, KENT or 100 MAIN ST, LAUREL, MISS.), or when its county is written only as Co with no other Maryland place (1 MAIN ST, HOWARD CO). The check is a fairness snapshot of the public record, not an appraisal, and not legal advice; the official SDAT record is authoritative.