Where do property data platforms get their data?

Property data comes from separate systems

Assessments, taxes, sales, deeds, permits, licenses, inspections, energy records, and building characteristics are created for different public programs. The records may use different account, parcel, building, address, permit, or instrument identifiers.

A platform must acquire, normalize, and link those records. Each step can add value, but each step can also hide source meaning if the product does not preserve it.

A common field does not mean a common source

Two products can show a field with the same label while using different sources, release dates, or derivation rules. An owner field may come from an assessor account, a deed index, or another licensed source. Those records do not support the same conclusion.

Ask whether the field is reported or derived, which public or licensed source supplied it, and whether an official record can be opened for review.

How Quoin handles Washington, DC

Quoin currently covers DC property tax accounts. It keeps official source identity and frozen release timing, then labels exact property links separately from building, multi-parcel, and proximity context.

Each supported fact can carry a source reference that expands into an official human portal, exact lookup inputs, and verification steps. API access is available by request, and the authenticated MCP is available now.

Questions to ask any provider

• Which source supplied this field?
• When was the source collected or released?
• Is the value reported, derived, or inferred?
• Does the record link exactly to this property?
• Can a reviewer reproduce the lookup in an official portal?