Property data source APIs: coverage, freshness, and limits

Know your data sources.

Each source has a page with its publisher, update schedule, coverage, known limits, and request fields. Coverage tells you where a source is available, not which fields a property will return. You can get the same details as JSON at /api/knowledge/data-sources.

Last verified September 9, 2026. That is when this list was last rebuilt from the ParcelOps source registry, not when each publisher last refreshed its own data.

tag: building-permits

Census Building Permits No auth
County-level residential building-permit authorizations, units, and construction value.
census building-permits residential housing county
2 methodsScheduled · every month
NYC Property Timeline No auth
One BBL timeline across recorded documents, permits, housing violations, and executed evictions.
new-york-city bbl acris deeds building-permits
2 methodsScheduled
US Municipal Open Data Discovery No auth
Find local property datasets or search normalized permit, inspection, and violation events in five US markets.
open-data socrata municipal zoning permits
8 methodsScheduled