API Reference

All endpoints require an API key via the X-API-Key header. Responses use a { data, meta } envelope. Click any endpoint for full request/response details.

Response Format

{
  "data": "...",
  "meta": {
    "requestId": "abc-123",
    "timestamp": "2026-02-21T12:00:00Z",
    "pagination": {
      "page": 1,
      "limit": 20,
      "total": 150,
      "totalPages": 8
    }
  }
}

Content Negotiation

Request format via query parameter (?format=xml) or Accept header. Priority: query param > Accept header > default (JSON).

JSON (all tiers)XML (starter+)CSV (starter+, list endpoints only)

Data Availability by Area Type

Not all data domains are available at every geographic level. This table shows which data types each area type supports.

Area Type	Demographics	Fair Market Rent	Migration	Mortgage	Employment
ZIP Code	✓	✓	—	—	—
County	✓	✓	✓	✓	✓
State	✓	—	✓	✓	✓
Census Tract	✓	—	—	✓	✓
Metro Area (CBSA)	✓	—	—	—	—
Place	✓	—	—	—	✓
Block Group	✓	—	—	—	✓

ZIP Codes

Search, lookup, and spatial queries for US ZIP codes

Method	Endpoint	Description	Tier
GET	/zip-codes	Search ZIP codes with filters	free
GET	/zip-codes/:zip	Get details for a single ZIP code	free
GET	/zip-codes/by-city	Get ZIP codes by city and state	free
GET	/zip-codes/by-coordinates	Find ZIP code at coordinates	free
GET	/zip-codes/distance	Calculate distance between two ZIP codes	starter
GET	/zip-codes/:zip/radius	Find ZIP codes within a radius	starter
POST	/zip-codes/batch	Batch lookup of multiple ZIP codes	enterprise
POST	/zip-codes/distance/matrix	Distance matrix for multiple origins/destinations	enterprise

Demographics

Population, income, housing, education, and employment data by ZIP code

Method	Endpoint	Description	Tier
GET	/demographics/:zip	Full demographics for a ZIP code	starter
GET	/demographics/:zip/population	Population data for a ZIP code	starter
GET	/demographics/:zip/income	Income data for a ZIP code	starter
GET	/demographics/:zip/housing	Housing data for a ZIP code	starter
GET	/demographics/compare	Compare demographics across ZIP codes	starter
POST	/demographics/aggregate	Aggregate demographics for ZIP codes	enterprise
GET	/demographics/area/:areaType/:geoid	Demographics for an area (county, state, CBSA, place)	starter
GET	/demographics/:zip/trend	Demographics trend for a ZIP code	starter
GET	/demographics/area/:areaType/:geoid/trend	Demographics trend for an area	starter
GET	/demographics/:zip/changes	Year-over-year changes for a ZIP code	starter
GET	/demographics/area/:areaType/:geoid/changes	Year-over-year changes for an area	starter

Boundaries

GeoJSON boundary polygons for ZIP codes, counties, and states with spatial operations

Method	Endpoint	Description	Tier
GET	/boundaries/zip/:zip	Get boundary polygon for a ZIP code	starter
GET	/boundaries/county/:fips	Get boundary polygon for a county	starter
GET	/boundaries/state/:abbr	Get boundary polygon for a state	starter
GET	/boundaries/containing	Find boundaries containing a point	starter
POST	/boundaries/intersecting	Find boundaries intersecting with geometry	enterprise
POST	/boundaries/point-in-polygon	Check if point is inside a boundary	enterprise
GET	/boundaries/viewport	Bulk viewport metrics for choropleth rendering	starter
GET	/search/areas	Unified area search across boundary types	starter

Market Data / FMR

Fair Market Rent data by ZIP code, county, metro area, and state — sourced from HUD

Method	Endpoint	Description	Tier
GET	/market/fmr/zip/:zip	Fair Market Rent by ZIP code	starter
GET	/market/fmr/county/:fips	Fair Market Rent by county FIPS code	starter
GET	/market/fmr/metro/:code	Fair Market Rent by metro/CBSA code	starter
GET	/market/fmr/state/:state	Fair Market Rent for all areas in a state	starter
GET	/market/fmr/:areaType/:areaCode/trend	Fair Market Rent trend data	starter

Geocoding

Forward and reverse geocoding with address validation and autocomplete

Method	Endpoint	Description	Tier
GET	/geocode	Forward geocode an address to coordinates	starter
GET	/geocode/reverse	Reverse geocode coordinates to an address	starter
GET	/geocode/autocomplete	Autocomplete address suggestions	starter
POST	/geocode/validate	Validate and normalize an address	starter
POST	/geocode/batch	Batch geocode multiple addresses	enterprise

Locations

Store, search, and query custom locations with spatial lookups

Method	Endpoint	Description	Tier
GET	/locations	List locations with filtering and pagination	starter
GET	/locations/:id	Get a single location	starter
GET	/locations/nearby	Find locations within a radius	starter
GET	/locations/search	Search locations by name or text	starter
POST	/locations	Create a new location	starter
PUT	/locations/:id	Update an existing location	starter
DELETE	/locations/:id	Delete a location	starter
POST	/locations/bulk	Bulk create locations	enterprise
DELETE	/locations/bulk	Bulk delete locations	enterprise

Mortgage Lending

HMDA mortgage lending metrics aggregated at tract, county, and state levels (2018–2024)

Method	Endpoint	Description	Tier
GET	/mortgage/area/:areaType/:geoid	Get mortgage lending summary for an area	business
GET	/mortgage/area/:areaType/:geoid/trend	Get mortgage lending trends across years	business
GET	/mortgage/years	Get available HMDA data years	business

Employment

LODES/LEHD employment profiles, commute flows, and workforce trends by area (2017–2022)

Method	Endpoint	Description	Tier
GET	/employment/area/:areaType/:geoid	Get employment summary for an area	business
GET	/employment/area/:areaType/:geoid/trend	Get employment trends across years	business
GET	/employment/area/:areaType/:geoid/flows/:direction	Get top commute flows for an area	business
GET	/employment/years	Get available LODES data years	business

Migration

IRS SOI county-to-county and state-to-state migration flows with income data

Method	Endpoint	Description	Tier
GET	/migration/:level/:fips/summary	Get migration summary for a county or state	business
GET	/migration/:level/:fips/:direction	Get top migration flows by direction	business
GET	/migration/:level/:fips/trends	Get migration trends across year pairs	business
GET	/migration/years	Get available migration year pairs	business

Environmental (EJScreen)

EPA EJScreen environmental justice indicators at block group level — air quality, cancer risk, and proximity to hazardous sites

Method	Endpoint	Description	Tier
GET	/environmental/area/:areaType/:geoid	Get environmental indicators for a block group	business
GET	/environmental/years	Get available EJScreen data years	business

Industry Employment (QCEW)

BLS Quarterly Census of Employment and Wages — county and state level industry employment, wages, and establishment counts

Method	Endpoint	Description	Tier
GET	/industry/area/:areaType/:geoid	Get industry employment data for a county or state	business
GET	/industry/years	Get available QCEW data years and quarters	business

Unemployment (LAUS)

BLS Local Area Unemployment Statistics — monthly county-level unemployment rates, labor force, and employment levels

Method	Endpoint	Description	Tier
GET	/unemployment/area/:areaType/:geoid	Get monthly unemployment data for a county or state	business
GET	/unemployment/latest/:areaType/:geoid	Get most recent unemployment data for an area	business
GET	/unemployment/years	Get available LAUS data years	business

Air Quality (PM2.5)

CDC tract-level annual PM2.5 concentration estimates from satellite-derived models

Method	Endpoint	Description	Tier
GET	/air-quality/area/:areaType/:geoid	Get PM2.5 air quality data for a census tract	business
GET	/air-quality/trend/:areaType/:geoid	Get PM2.5 trend for a census tract across all available years	business
GET	/air-quality/years	Get available PM2.5 data years	business

67 endpoints across 13 domains

ZIP Codes: 8Demographics: 11Boundaries: 8Market Data / FMR: 5Geocoding: 5Locations: 9Mortgage Lending: 3Employment: 4Migration: 4Environmental (EJScreen): 2Industry Employment (QCEW): 2Unemployment (LAUS): 3Air Quality (PM2.5): 3