What data sources does RentHistory.org aggregate?

DHCR rent registrations, ACRIS (all 14 endpoints), HPD records and violations, DOB records and violations, and OCA court data where available.

Is there a professional API?

Yes. Pro API access is available for attorneys, research teams, newsrooms, and organizations. Contact us for keys, rate limits, and pricing.

NYC housing data tools for professionals.

Rent history analysis, landlord network mapping, and real-time violation tracking — built for tenant attorneys, organizers, researchers, and agents.

Run the Rent History Analyzer Create free account

In New York City, a DHCR rent history is the primary document for identifying illegal rent increases, fraudulent deregulation, and rent overcharges in rent stabilized apartments. Between 2002 and 2017, NYC lost 173,500 rent regulated apartment units. RentHistory.org analyzes DHCR rent histories, cross-references HPD violations, DOB permits, and ACRIS ownership records, and surfaces the patterns that indicate rent stabilization fraud. Used by tenant attorneys, housing organizers, researchers, and real estate professionals across all five boroughs.

Tools

Screen a rent history in under a minute.

Paste a DHCR report, get overcharge math, IAI gaps, deregulation timeline, and REC-1 / RA-89 drafts. Eviction petition parsing included.

— Rent History Analyzer™ v4.3

Open Analyzer →

Map a landlord's full entity structure.

LLC unmasking, shared principals, ACRIS-linked mortgages, and litigation history across the portfolio. Export portfolios as CSV or JSON.

— Landlord Network Explorer™ v1.3

Open Network Explorer →

Monitor buildings and landlords continuously.

New violations, permits, registration changes, court filings, mortgage activity — pushed to email, dashboard, or SMS.

— Watchdog Engine™

Configure monitoring →

Visualize violations at the block and tract level.

HPD, DOB, and 311 density mapped across the five boroughs. Filter by violation class, timeframe, and landlord portfolio.

— Citywide Violation Heat Map

Open heat map →

Pull a full building record by address or BBL.

HPD, DOB, ACRIS, DHCR registrations, 311, and ownership history in a single record. No login required.

— Building Record Search

Open search →

Find listings limited to rent-stabilized units.

Verified rent-stabilized listings across all five boroughs, cross-referenced against DHCR registration data.

— SteadNest™

Browse listings →

Data & Methodology

Sources

DHCR — rent history documents and regulatory status data as released
ACRIS — all 14 endpoints (deeds, mortgages, UCC, parties, legals, remarks, cross-refs, etc.)
HPD — registrations, violations, complaints, litigation
DOB — permits, violations, ECB, certificates of occupancy
OCA — civil and housing court filings where available

Coverage

ACRIS records indexed across all 14 endpoints
HPD registration, violation, and complaint data for NYC multiple dwellings
DHCR rent history documents available to RentHistory.org through public release and user uploads — not a complete DHCR registry

Known limitations

RentHistory.org indexes public records and privately-contributed documents. DHCR rent histories reflect what the agency has released or what users have uploaded, not a live registry. ACRIS indexes may miss OCR artifacts in scanned legacy documents. Entity matching across LLCs is deterministic on exact strings and probabilistic on fuzzy matches — both confidence levels are surfaced in the API and UI.

Full methodology & changelog →

We've been building a tool like this at Brick Underground for more general purpose check-ins on properties using open data.. but we don't cover this data yet.

— Justin DeMaris
Founder, Flexpress
Tech leader, Britannica
Advisor, Brick Underground

Your Privacy Comes First

Searches, downloads, and monitoring are never visible to subjects of research. API usage is logged only for abuse prevention.

NYC housing data tools for professionals.

Tools

Data & Methodology

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