ZIP-Codes.com

Credits for Research & Public-Interest Work

For academics, journalists, nonprofits & civic projects · reviewed case-by-case

The ZIP Codes API gives you 14 years of US Census ACS demographics (2011–2024) — social, economic, housing, and demographic profiles, roughly 500 fields per ZIP per year — for every US ZIP and Canadian postal code, through one REST call. It's built for reproducible research, reporting, and public-interest analysis. If a project outgrows the free tier, we review research-credit requests case by case.

Why researchers use this data

  • 14 years normalized for you. ACS 5-Year profiles DP02–DP05, 2011–2024 — we reconcile the year-to-year Census variable drift and the 2020 GEO_ID format change, so a longitudinal series just lines up.
  • Margins of error preserved. Per-ZIP responses return the MOE for every field; Census-suppressed values come back as explicit null, never zero.
  • Works per-ZIP and across a radius. Query one ZIP with /zip, or aggregate every ZIP inside a radius with /radius.
No GIS software required. In /radius spatial mode the API intersects your radius with actual ZIP/FSA boundary polygons and weights the ACS aggregate by each ZIP's pct_inside — a ZIP 30% inside the circle contributes 30% of its population, not all-or-nothing. See the runnable example →

Most projects fit comfortably in the free tier — 2,500 credits/day, no credit card. Start there, and reach out when a project needs more.

What people build with it

Academics & students

A 14-year longitudinal dataset in seconds — e.g. housing-cost (DP04) change for every ZIP in a state, or income shifts around a campus — for theses, dissertations, and published research.

Data journalists

The demographic makeup within a few miles of a toxic-release site, hospital closure, or new development — coverage-weighted by real boundaries — plus "decade of change" maps off the 14-year series.

Nonprofits

Who actually lives inside your service area — population and need weighted by how much of each ZIP falls in your catchment — for grant-targeting and program planning.

Civic & public-sector

ZIP or address to congressional, state-legislative, and school districts; radius service-area lookups; reproducible open-data tools and classroom notebooks.

What we offer

  • The free tier, always. 2,500 credits/day, no card — yours whether or not you ever contact us.
  • Case-by-case extended credits when a project genuinely needs more than the free tier. We don't publish a fixed grant size — every request is reviewed individually, and any grant is at our discretion.
  • A point of contact for questions about the data, methodology, or the ZIP-vs-ZCTA caveats.

We'd rather size each grant to the actual project than promise a number up front, so please tell us what you're working on (details below) and we'll work it out together.

What we ask in return

A simple, good-faith exchange — not a contract:

  • A citation or acknowledgement in any published work that uses the data (suggested text below).
  • A link back to the API where a link naturally fits — a methods note, a footer, a project page.
  • We'd love to see what you build. Tools, notebooks, dashboards, papers — send them our way. With your permission, we may feature standout projects.

Suggested acknowledgement

Copy whichever fits your format:

Plain acknowledgement
Demographic data: US Census Bureau ACS 5-Year Estimates, accessed via ZIP Codes API (Zip-Codes.com), https://www.zip-codes.com/api/
BibTeX
@misc{zipcodesapi,
  title  = {ZIP Codes API — US Census ACS demographics by ZIP code},
  author = {{Zip-Codes.com}},
  note   = {US Census Bureau ACS 5-Year Estimates},
  url    = {https://www.zip-codes.com/api/},
  year   = {2026}
}

How to apply

Email jharris@zip-codes.com with a few details so we can size a grant to your project:

Copy-paste email template
Subject: Research credits request — [project name]

Affiliation / organization:
Project summary:
Data needed (profiles / years / geography):
Expected volume (a rough estimate is fine):
Intended output (paper, story, tool, class):
Citation or link possible?:
Anything already published or in progress:

Email your request

We read every request personally and reply — usually within a few business days. Requests are evaluated individually; sending one doesn't guarantee a grant.

Try the data first

You don't need to wait for a reply to start. Our open sample repo has a runnable notebook — pull a 14-year demographic series for any US ZIP in about ten lines of Python, no signup required:

Ready to get started?

Sign up for free and start making API calls in minutes. No credit card required.