API Reference

Authentication

Pass your API key in the Authorization header on every request. Free accounts have no API access. Requests without a valid Pro key return 401.

curl "https://lotlyze.com/api/lookup?query=3016070023" \
  -H "Authorization: Bearer YOUR_API_KEY"

const API_KEY = "YOUR_API_KEY"; // from lotlyze.com/account

const res = await fetch(
  "https://lotlyze.com/api/lookup?query=3016070023",
  { headers: { Authorization: `Bearer ${API_KEY}` } }
);
const data = await res.json();

import httpx

API_KEY = "YOUR_API_KEY"  # from lotlyze.com/account
HEADERS = {"Authorization": f"Bearer {API_KEY}"}

data = httpx.get(
    "https://lotlyze.com/api/lookup",
    params={"query": "3016070023"},
    headers=HEADERS,
).json()

Where to find your key

1. Sign in at lotlyze.com/sign-in
2. Go to My Account
3. Copy the key from the API Key section
4. Use it in the Authorization: Bearer <key> header

Error responses

Resolve any NYC address, BBL, or BIN to canonical identifiers.

Parameters

Example

curl "https://lotlyze.com/api/lookup?query=250+Broadway+Manhattan" \
  -H "Authorization: Bearer YOUR_API_KEY"

const res = await fetch(
  "https://lotlyze.com/api/lookup?query=250+Broadway+Manhattan",
  { headers: { Authorization: "Bearer YOUR_API_KEY" } }
);
const { bbl, bin, label } = await res.json();

Response

{
  "type": "address",
  "bbl": "1001247502",
  "bin": "1001408",
  "label": "250 B'WAY, New York, NY, USA",
  "source": "geosearch"
}

For a BBL or BIN query, type is bbl or bin, source is pad, and there is no label. The bin field can be null when no building is on file for the lot. An unknown BIN or address returns 404.

Look up the best public evidence of a Chicago 2–6 unit residential building's dwelling-unit count, plus building facts, the owner of record, the Assessor's value, the last permit for each building system, permits, violations, and sales history. Zoning, nearby district classes, parcel coordinates, and 2021 parcel outlines are available for all Chicago property classes, including those with an unsupported unit count. Optionally compare user-entered listing figures. Requires a Pro API key.

Parameters

Real example: 2121 N Laporte Ave, Chicago

curl "https://lotlyze.com/api/chicago-units?query=2121+N+Laporte+Ave,+Chicago" \
  -H "Authorization: Bearer YOUR_API_KEY"

curl "https://lotlyze.com/api/chicago-units?query=13332200130000" \
  -H "Authorization: Bearer YOUR_API_KEY"

Listing comparison example

/api/chicago-units?query=13233210110000&price=799000&units=2&bedrooms=6&baths=3&landSqft=6250&rent1=1800&rent2=1800

These are user assumptions, not verified listing data. Listing inputs do not alter the shared report snapshot. Numeric inputs use plain decimal numbers without currency signs, commas, or exponents; duplicate inputs are rejected. Website listing comparison is currently paused; this API contract remains available. Query strings may appear in access logs; do not include private tenant information.

Unlevered return example

/api/chicago-units?query=13233210110000&investmentPrice=600000&unitRent1=2000&unitRent2=2000&vacancyPct=5&expensePct=30&annualTax=10000

These assumptions yield $48,000 gross rent/year, $45,600 collected rent, $13,680 non-tax expenses, $10,000 tax, $21,920 NOI, 3.6533% cap rate, and 12.5 GRM. Underwriting is separate from listing comparison and never saved in the shared public snapshot. Missing inputs or benchmarks producestatus: incomplete with explicit missing reasons; unknown is not zero. Blank price uses Assessor market value. Blank unit rents use HUD when bedrooms are specified, otherwise the ACS tract median gross rent if available; no unit bedroom mix is inferred. Blank tax, vacancy, and expenses use the report's public estimates/model. Results identify applied price and rent sources; entered values (including zero where allowed) take precedence. No debt, capital repairs, closing costs, or income taxes are included.

Response excerpt

Public source records checked October 19, 2026. Permit 101073592, issued April 7, 2026, states a total of 3 dwelling units; the Assessor lists 2. The permit takes precedence and mismatch: true flags the disagreement. Owner fields are placeholders here; geography is an illustrative shape and its polygon features are omitted for brevity. Live results may change as source records are updated. An issued permit does not prove the work was completed or establish legal occupancy.

{
  "status": "ok",
  "pin": "13332200130000",
  "pins": [
    "13332200130000"
  ],
  "address": "2121 N LAPORTE AVE 1",
  "assessorClass": "211",
  "units": 3,
  "source": "permit",
  "assessorUnits": 2,
  "mismatch": true,
  "permit": {
    "units": 3,
    "permitNumber": "101073592",
    "issueDate": "2026-04-07",
    "text": "SRP 2019 CBRC: INTERIOR & EXTERIOR ALTERATIONS IN EXISTING 2-STORY BRICK MULTI-UNIT RESIDENCE (2DU) IN ORDER TO CONVERT EXISTING UNFINISHED FIRST FLOOR LEVEL INTO NEW DWELLING UNIT FOR TOTAL OF 3 DWELLING UNITS. MECHANICAL, ELECTRICAL & PLUMBING, CONVERT EXISTING REAR OPEN WOOD PORCH TO REAR ENCLOSED WOOD PORCH PER PLANS.OCCUPANCY CLASSIFICATION: R-5 CONSTRUCTION TYPE: III-B"
  },
  "facts": {
    "yearBuilt": 1914,
    "buildingSqft": 2405,
    "landSqft": 3780,
    "bedrooms": 4,
    "fullBaths": 2,
    "halfBaths": 0,
    "heat": "Warm Air Furnace",
    "airConditioning": "No Central A/C",
    "roof": "Shingle + Asphalt",
    "basement": "Full, unfinished",
    "attic": "None",
    "porch": "None",
    "garage": "2 cars, detached, frame",
    "exteriorWall": "Masonry",
    "condition": "Average"
  },
  "owner": {
    "name": "OWNER NAME",
    "mailingAddress": "MAILING ADDRESS, BOLINGBROOK, IL 60490",
    "likelyOwnerOccupied": false
  },
  "assessment": {
    "year": 2026,
    "stage": "mailed",
    "assessedValue": 38000,
    "marketValue": 380000
  },
  "lastPermitBySystem": {
    "roof": null,
    "porch": {
      "permitNumber": "101073592",
      "issueDate": "2026-04-07"
    },
    "masonry": null,
    "electrical": {
      "permitNumber": "101073592",
      "issueDate": "2026-04-07"
    },
    "plumbing": {
      "permitNumber": "101073592",
      "issueDate": "2026-04-07"
    },
    "heating": {
      "permitNumber": "101073592",
      "issueDate": "2026-04-07"
    },
    "windows": null
  },
  "checkedAt": "2026-10-19T13:07:15.000Z",
  "listing": null,
  "comparison": [],
  "location": {
    "latitude": 41.9198,
    "longitude": -87.7406,
    "sourceYear": 2026
  },
  "geography": {
    "status": "available",
    "zoning": {
      "districts": [
        {
          "code": "RT-4",
          "description": "Residential two-flat / townhome"
        }
      ],
      "nearbyDistricts": [
        "RS-3",
        "RT-4"
      ],
      "nearbyRadiusMeters": 402.336,
      "density": {
        "lotSqftPerUnit": 1000,
        "approximateUnits": 3
      },
      "sourceUrl": "https://data.cityofchicago.org/d/dj47-wfun",
      "rulesUrl": "https://www.chicago.gov/city/en/depts/dcd/supp_info/zoning_ordinance.html"
    },
    "parcelOutlines": {
      "year": 2021,
      "sourceUrl": "https://datacatalog.cookcountyil.gov/d/77tz-riq7",
      "missingPin10s": [],
      "geojson": {
        "type": "FeatureCollection",
        "features": []
      }
    },
    "errors": []
  },
  "disclaimer": "Best public evidence, not a certified legal unit count.",
  "verifyUrl": "https://www.chicago.gov/city/en/depts/dcd/supp_info/legal-unit-count.html"
}

Response fields

City permits and violations match the street address and may miss other addresses on the parcel. A property can span several Cook County PINs: a tied side-lot PIN returns its key PIN's report, and pins lists them all. Reports refresh after 24 hours; checkedAt shows when the sources were last checked. This is not a certified legal unit count: request City verification before relying on it for a purchase or zoning decision.

Geography is evaluated at the Assessor's parcel point, not every boundary of a split-zoned lot. The density screen uses base lot area per dwelling unit for RS-1, RS-2, RS-3, RT-3.5, RT-4, RM-4.5, and RM-5 only; other or multiple districts return density: null. It is not an allowed/legal-unit count or ADU determination. Tied tax PINs need not be one zoning lot.geography.errors identifies missing sources, coordinates, or outdated/missing outlines. Failed geography sources produce an explicit partial/unavailable result rather than removing the core report.

context is available for every Chicago class. Transit distances are straight-line; walking estimates assume 3 mph, not a walking route. CMAP bands split the 10–130 range into thirds, not Walk Score. Traffic, rail, and airport data are noise proxies, not measured building sound. FEMA/First Street indicators are not insurance advice. Building-related 311 requests are address-matched allegations, not confirmed violations; the latest 50 are returned with a truncation flag. Each metric retains its source vintage; some are older than the report check.

market is for class 211. Comps use the same Assessor neighborhood and the preceding 18 months, exclude multi-parcel and Assessor-flagged sales, remove tied buildings, and keep one latest sale per PIN. Quartiles use linear interpolation; weightedPricePerUnit weights each sale linearly from 0.5 (oldest) to 1 (newest). Ten properties are ranked by unit-count match, then building area. Statistics cover all joined eligible properties (at most 1,000 input sales, with truncated flagged). Current Assessor facts may differ from sale-date facts. The 12-calendar-year median sale trend is not a repeat-sales index; the current year is partial. Tax estimates multiply the property's latest AV by the 2024 equalizer 3.0355 and Chicago average composite rate 6.619%, before exemptions. They mix assessment/rate years and are not actual bills or forecasts; check the Treasurer for each PIN. Income defaults are township medians for 7+-unit low-rise apartments, not observed 2–6-flat operations.

rentBenchmarks comes from an offline annual bake, not per-request provider calls. HUD SAFMR is a ZIP gross-rent benchmark, not asking rent; ACS is a lagged tract median from overlapping five-year samples on 2020 tract boundaries. Nominal histories retain each fiscal/vintage year. HUD fallback requires an explicit per-unit bedroom count and includes tenant-paid utilities. Provider data not yet baked returns explicit missing statuses rather than estimated rents. The Assessor model expense ratio is treated as all-in: non-tax expense defaults to max(0, model ratio × collected rent − taxes). A supplied expensePct instead means non-tax expenses, with taxes deducted separately.

status is ok, unsupported (outside the supported residential class or outside Chicago), or not_found. These outcomes return HTTP 200; a unit count can be null when evidence is unavailable. Missing or overlong queries, unsupported listing URLs, and invalid listing inputs return 400; upstream data failures return 502. Without a valid Pro key, requests return 401.

NYC all-in-one: resolves an address, BBL, or BIN, then returns its identifiers, ACRIS records, and DOB records in one request.

Parameters

Example

curl "https://lotlyze.com/api/property?query=534+Kosciuszko+St+Brooklyn" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "lookup": {
    "address": "534 KOSCIUSZKO STREET, Brooklyn, NY, USA",
    "bbl": "3016070023",
    "bbl_formatted": "3-01607-0023",
    "bin": "3043452",
    "borough": "Brooklyn",
    "block": "01607",
    "lot": "0023",
    "latitude": 40.6926,
    "longitude": -73.932574
  },
  "acris": {
    "records": [
      {
        "id": "2019061400456001",
        "date": "2019-06-14",
        "type": "DEED",
        "description": "DEED",
        "party1": "SELLER NAME",
        "party2": "BUYER NAME",
        "amount": 1250000,
        "formatted_amount": "$1,250,000"
      }
    ],
    "count": 1
  },
  "dob": {
    "permits": [],
    "jobFilings": [],
    "dobNow": [],
    "violations": [],
    "complaints": []
  }
}

address, latitude, and longitude are only filled for address queries. ACRIS records here have no category and use formatted_amount. Each DOB list holds up to 20 raw NYC Open Data rows since January 1, 2020, newest first. An unknown address or BIN returns 404.

Fetch ACRIS deed and document records for a property.

Parameters

Example

curl "https://lotlyze.com/api/acris?bbl=1000477501" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "bbl": "1000477501",
  "records": [
    {
      "id": "2023012700123456",
      "date": "2023-01-27",
      "type": "DEED",
      "description": "DEED",
      "category": "deed",
      "party1": "SELLER NAME",
      "party2": "BUYER NAME",
      "amount": 4500000,
      "formattedAmount": "$4,500,000"
    }
  ],
  "count": 1
}

Records are newest first. category is deed, mortgage, lien, ucc, satisfaction, or other. A BBL with no ACRIS records returns {"bbl": "…", "records": []} without a count.

Fetch DOB permits, job filings, violations, and complaints for a building.

Parameters

Example

curl "https://lotlyze.com/api/dob?bin=1001074" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "bin": "1001074",
  "permits": [
    {
      "job__": "102657000",
      "permit_type": "SG",
      "issuance_date": "2000-10-20",
      "source_system": "DOB_Socrata"
    }
  ],
  "jobFilings": [
    {
      "job__": "140641321",
      "job_type": "A3",
      "latest_action_date": "12/06/2018",
      "source_system": "DOB_Socrata"
    }
  ],
  "dobNow": [
    {
      "job_filing_number": "M00001019-I1",
      "work_permit": "M00001019-I1-FN",
      "approved_date": "2017-10-30T12:13:00.000",
      "source_system": "DOB_NOW"
    }
  ],
  "violations": [],
  "complaints": [
    {
      "complaint_number": "1411462",
      "status": "CLOSED",
      "date_entered": "12/03/2015",
      "source_system": "DOB_Socrata"
    }
  ]
}

Each list holds up to 20 raw NYC Open Data rows, newest first, using the source dataset's field names, plus a source_system tag. Rows are shortened above.

HPD housing-code violations and complaints for a property.

Parameters

Example

curl "https://lotlyze.com/api/hpd?bbl=3016070023" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "bbl": "3016070023",
  "violations": [
    {
      "orderId": "12345678",
      "class": "B",
      "description": "§ 27-2026 ADM CODE REPAIR THE LEAKY FAUCET IN THE BATHROOM",
      "inspectionDate": "2024-05-02",
      "issuedDate": "2024-05-03",
      "status": "NOV SENT OUT",
      "apartment": "2",
      "source": "HPD"
    }
  ],
  "complaints": [
    {
      "complaintId": "3447477",
      "type": "EMERGENCY",
      "status": "CLOSE",
      "openedDate": "2006-09-13",
      "closedDate": "2006-09-17",
      "source": "HPD"
    }
  ]
}

Up to 50 violations, newest inspection first. Complaint problem rows are grouped by complaint, so one complaint can list several types; closedDate is empty until the complaint closes.

ECB/OATH violations for a building, with the total unpaid balance.

Parameters

Example

curl "https://lotlyze.com/api/ecb?bin=3043452" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "bin": "3043452",
  "violations": [
    {
      "violationId": "34847088Z",
      "respondent": "OWNER NAME",
      "description": "FAILURE TO MAINTAIN BLDG IN CODE COMPLIANT MANNER.",
      "violationType": "Construction",
      "agency": "DOB",
      "issueDate": "20100423",
      "hearingDate": "20100614",
      "penaltyTotal": 5000,
      "balanceDue": 0,
      "status": "RESOLVE",
      "source": "ECB"
    }
  ],
  "totalBalanceDue": 0
}

Up to 50 violations, newest first. Dates are YYYYMMDD strings, as published, and totalBalanceDue is the sum of balanceDue across the returned violations.

NYC Department of Finance assessment for a property.

Parameters

Example

curl "https://lotlyze.com/api/tax?bbl=3016070023" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "bbl": "3016070023",
  "assessment": {
    "bbl": "3016070023",
    "taxClass": "1",
    "marketValue": 1355000,
    "assessedValue": 81300,
    "exemptValue": 0,
    "taxableAssessedValue": 21919,
    "annualTax": 4349.39,
    "annualTaxIsEstimate": true,
    "assessmentYear": "2027",
    "taxRateYear": "25/26",
    "taxRatePercent": 19.843,
    "has421a": null,
    "stabilizationIndicator": null,
    "source": "DOF"
  }
}

assessment is null when Finance has no record for the BBL. The annual tax is an estimate: the latest published rate for the tax class is applied to the DOF taxable assessed value, and does not account for property-specific credits. The current assessment dataset does not identify 421-a exemptions, so has421a and stabilizationIndicator are null.

NYC full summary: ACRIS, DOB, HPD, ECB, and Finance tax data in a single request. Resolves BBL to BIN automatically.

Parameters

Example

curl "https://lotlyze.com/api/summary?bbl=3016070023" \
  -H "Authorization: Bearer YOUR_API_KEY"

import httpx

API_KEY = "YOUR_API_KEY"

data = httpx.get(
    "https://lotlyze.com/api/summary",
    params={"bbl": "3016070023"},
    headers={"Authorization": f"Bearer {API_KEY}"},
).json()

print(data["acris"][0]["date"])   # most recent deed date
print(len(data["dob"]["violations"]))

Response

{
  "bbl": "3016070023",
  "bin": "3043452",
  "borough": "Brooklyn",
  "acris": [
    {
      "id": "2019061400456001",
      "date": "2019-06-14",
      "type": "DEED",
      "description": "DEED",
      "category": "deed",
      "party1": "SELLER NAME",
      "party2": "BUYER NAME",
      "amount": 1250000,
      "formattedAmount": "$1,250,000"
    }
  ],
  "hpd": {
    "violations": [],
    "complaints": [
      {
        "complaintId": "3447477",
        "type": "EMERGENCY",
        "status": "CLOSE",
        "openedDate": "2006-09-13",
        "closedDate": "2006-09-17",
        "source": "HPD"
      }
    ]
  },
  "ecb": {
    "violations": [],
    "totalBalanceDue": 0
  },
  "tax": {
    "bbl": "3016070023",
    "taxClass": "1",
    "marketValue": 1355000,
    "assessedValue": 81300,
    "exemptValue": 0,
    "taxableAssessedValue": 21919,
    "annualTax": 4349.39,
    "annualTaxIsEstimate": true,
    "assessmentYear": "2027",
    "taxRateYear": "25/26",
    "taxRatePercent": 19.843,
    "has421a": null,
    "stabilizationIndicator": null,
    "source": "DOF"
  },
  "dob": {
    "permits": [
      {
        "job__": "321234567",
        "issuance_date": "2021-03-02",
        "source_system": "DOB_Socrata"
      }
    ],
    "jobFilings": [],
    "dobNow": [],
    "violations": [],
    "complaints": []
  }
}

Unlike the single-source endpoints, acris is a plain array of records, HPD violations omit issuedDate, ECB violations omit status, and tax is the flat assessment plus bbl (or null). Each DOB list holds up to 20 rows, newest first, tagged with source_system.

Look up to 50 NYC BBLs in a single request: identifiers, ACRIS records, and DOB records for each. Send a JSON body with POST, or a comma-separated bbls parameter with GET.

Parameters

Example

curl -X POST "https://lotlyze.com/api/bulk" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"bbls": ["3016070023", "1004770001", "4015670023"]}'

curl "https://lotlyze.com/api/bulk?bbls=3016070023,1004770001" \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "count": 1,
  "results": [
    {
      "bbl": "3016070023",
      "ok": true,
      "data": {
        "bbl": "3016070023",
        "bbl_formatted": "3-01607-0023",
        "bin": "3043452",
        "borough": "Brooklyn",
        "block": "01607",
        "lot": "0023",
        "acris": {
          "records": [
            {
              "id": "2019061400456001",
              "date": "2019-06-14",
              "type": "DEED",
              "description": "DEED",
              "party1": "SELLER NAME",
              "party2": "BUYER NAME",
              "amount": 1250000,
              "formatted_amount": "$1,250,000"
            }
          ],
          "count": 1
        },
        "dob": {
          "permits": [],
          "jobFilings": [],
          "dobNow": [],
          "violations": [],
          "complaints": []
        }
      }
    }
  ]
}

Every result has ok. Successful results carry data; a BBL whose lookup failed carries error instead, without failing the whole request. ACRIS records use formatted_amount, and each DOB list holds up to 20 raw NYC Open Data rows since January 1, 2020. A missing or malformed list, more than 50 BBLs, or any invalid BBL returns 400.