{"uid":"cap_G9Rou47bXRAYHOyfLOmbY","slug":"hud-usps-zip-code-crosswalk-resolver-64cb5497","name":"HUD-USPS ZIP Code Crosswalk Resolver","description":"Resolve a US ZIP code to the census tract(s), county, CBSA (metro), and congressional district it covers — each with HUD-USPS allocation ratios (by residential, business, other, and total address counts). A ZIP is a mail-delivery route set, not a polygon, so it spans multiple geographies; the ratios tell you how much of the ZIP falls in each — the canonical join when you have a ZIP but a dataset is keyed by county/tract/district. Source: HUD-USPS ZIP Crosswalk (public domain).","url":"https://2s.io/api/geo/zip-resolve","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","queryParams"],"properties":{"type":{"const":"http"},"method":{"const":"GET"},"queryParams":{"required":["zip"],"properties":{"zip":{"type":"string","description":"5-digit US ZIP code."}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.012","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":{"p10Cents":"1.2000","medianCents":"1.2000","p90Cents":"1.2000","minCents":"1.2000","maxCents":"1.2000","p95Cents":"1.2000","sampleCount":1,"varies":false,"failureChargeRate":1},"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.012/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.012","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.012","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_7ByvRlxqYA-TkIJO8bGDb","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.012","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Resolves a US ZIP code to overlapping census tracts, counties, CBSAs (metro areas), and congressional districts with HUD-USPS allocation ratios by address type","exampleAgentPrompt":"What census tracts, county, metro area, and congressional district does ZIP code 90210 fall in — and what are the HUD-USPS allocation ratios showing how much of that ZIP is in each geography?","exampleUseCases":null,"resultDescription":"A list of geographic units (census tracts, counties, CBSAs, congressional districts) that overlap the given ZIP code, each with HUD-USPS allocation ratios broken down by residential, business, other, and total address counts — indicating what fraction of the ZIP falls within each geography.","failureModes":["Invalid or non-existent ZIP code returns an error or empty result","ZIP codes for PO Boxes or unique ZIP codes (e.g. for large organizations) may have unusual or no crosswalk data","Recently retired or newly created ZIP codes may not appear in the HUD-USPS dataset","Missing 'zip' query parameter returns a 400 or validation error"],"whenToPreferThis":"Use this endpoint when you have ZIP-coded data and need to join it to datasets keyed by county FIPS, census tract, CBSA, or congressional district — especially when you need proper allocation ratios to handle ZIP codes that span multiple geographies. Prefer this over simple centroid-based lookups when accuracy of split-geography attribution matters.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T07:16:39.185Z","isFirstParty":false}