US Census Bureau · Rate Limits

Us Census Bureau Rate Limits

The Census Bureau does not publish numeric request-per-minute / quota thresholds for the Census Data API, Microdata API, Geocoder, TIGERweb, or Population Clock. Operational guidance is qualitative — keys are free and one per email, and the Terms of Service note that the Bureau "reserves rights to monitor usage, block access for policy violations, modify terms unilaterally, and terminate service at its discretion." Heavy users are advised to batch via the Geocoder /addressbatch endpoint (up to 10,000 addresses per request) and to spread the load over time.

Us Census Bureau Rate Limits is the machine-readable rate-limit profile for US Census Bureau on the APIs.io network, conforming to the API Commons Rate Limits specification.

It captures 5 rate-limit definitions.

The profile also includes 4 backoff/retry policies defined.

Tagged areas include Government, Open Data, and Rate Limiting.

5 Limits
GovernmentOpen DataRate Limiting

Limits

The user guide recommends batching variables in the `get` clause (up to 50 variables per request) and using `group(...)` to fetch entire tables in one call rather than per-variable queries.
No API key required for the Geocoder. Server-side request timeouts apply; long-running single requests may be terminated.
Multipart CSV upload; the Census Bureau publishes the 10,000-address limit per request in the Geocoding Services API user guide.
ArcGIS Server defaults apply; large feature-set queries may be truncated by the server-side `maxRecordCount` (typically 1,000-2,000 features per page).
Public JSON feed; recommended to cache client-side.

Policies

Acceptable use
Census data may not be used to identify any individual person, household, business, or other entity, alone or combined with other datasets.
Attribution
Applications must display the disclaimer: "This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau."
Modified content
Applications must not attribute modified Census Bureau content back to the Census Bureau.
Key sharing
Keys are issued per email; sharing is discouraged but not technically enforced.

Sources

Work with this as data

Every rate limit here is available over the APIs.io API and to AI agents over MCP.

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Tools for rate limits

4 MCP tools reach this
  • find_rate_limitsBrowse and filter every rate limit in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
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Call it yourself

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This rate limit 
curl "https://apis.io/api/v1/rate-limits/us-census-bureau-rate-limits"
All rate limits 
curl "https://apis.io/api/v1/rate-limits?limit=25"

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