API for US ZIP, ZIP+4, and Canadian postal code data. One unified endpoint set covers North America — no separate APIs by country or data type.

What it does

• Address validation and standardization — production-grade parser with ZIP+4 append, refreshed monthly
• Radius search — centroid haversine and true spatial polygon intersection. Returns ZIPs/FSAs within range, with per-result pct_inside overlap percentage for spatial queries
• Unified lookup endpoint — accepts US ZIP, ZIP+4, Canadian FSA, full Canadian postal codes, or latitude/longitude inputs
• Autocomplete/typeahead — cities, counties, metros, states, FSAs, ZIPs
• Point-to-point distance — between any two postal points
• Census ACS demographics — 2011–2024, 542 fields per ZIP across income, education, housing, social, and economic profiles
• Boundary lookups — Census tracts, congressional districts, state legislative areas, school districts — with computed intersection percentages per ZIP

What makes it different

• Licensed commercial data — not commodity or scraped sources
• Canadian postal coverage — most peers in this space are US-only
• True spatial radius — not just centroid haversine
• 14 years of historical ACS depth via API — unusual outside of raw Census downloads
• One endpoint for all of North America — no country-detection or input-routing logic to maintain on the client side

Pricing

• Free — 2,500 lookups/day, no credit card required, no expiry
• Developer — $49/mo, 100K credits, 300/min
• Professional — $149/mo, 350K credits, 300/min
• Business — $499/mo, 1.5M credits, 600/min
• Credit packs — one-time, from 25K ($19) up to 2M ($799)

Resources

• Docs
• OpenAPI spec
• Postman collection

ZipCheckup analyzes 50+ federal data sources (EPA, FEMA, CDC, USGS, Census) to generate free home safety reports for all 42,679 U.S. ZIP codes. Covers water quality, lead risk, PFAS contamination, flood risk, radon, wildfire, earthquake, mold, and 9 more safety categories. 283,000+ pages, updated daily.