HomeSight

Zillow's public research division releases monthly housing statistics at the ZIP code level — the most granular publicly available housing dataset in the U.S. All five metrics HomeSight tracks come from this source.

The U.S. Census Bureau publishes TIGER/Line shapefiles containing ZIP Code Tabulation Area (ZCTA) boundary polygons — the geographic shapes drawn on the map for each ZIP code.

An open geographic database providing coordinates, city names, and state associations for every U.S. ZIP code — used to center the map when you search a ZIP and populate the city labels in tooltips and panels.

The UK government's official record of every residential property transaction in England & Wales since 1995 — over 31 million sales. HomeSight aggregates these transactions to postcode-sector level monthly medians to produce the UK heatmap and appreciation history.

Open boundary polygons for every UK postcode sector, distributed via the University of Edinburgh DataShare. HomeSight uses these to draw the sector shapes on the UK map. Postcode sectors (e.g. SW1A 1) are derived from full postcodes by taking the outward code plus the first digit of the inward code — roughly equivalent in granularity to U.S. ZIP codes.