Census Gov Census Data API
★ Only Publicly Available OpenAPI DocumentData EnrichmentAddress ValidationapiKey5 EndpointsREST
For Agents
Query U.S. Census Bureau demographic, economic, and housing datasets by year, dataset, variable, and geography. Discover available datasets, variables, and geographic levels.
Use for: I need to query American Community Survey 5-year estimates for a county, List all variables available in a specific Census dataset, Find population by ZIP code from the Decennial Census, Retrieve median household income for every state
Not supported: Does not handle address geocoding, EHR records, or tax filing — use for querying U.S. Census Bureau public datasets by variable and geography only.
Jentic publishes the only available OpenAPI specification for the U.S. Census Bureau Data API, keeping it validated and agent-ready. The Census Data API provides access to dozens of public datasets, including the American Community Survey (ACS), Decennial Census, and County Business Patterns. Queries are scoped by dataset vintage (year) and identifier, and can request specific variables aggregated to a chosen geographic level — state, county, tract, ZIP code tabulation area, and more. Five core endpoints cover dataset discovery, variable listing, geography listing, group listing, and the data query itself.
Install Jentic One Beta
Connect the Census Data API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Census Data API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
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Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Census Data API.
Discover every public Census dataset and its vintage via /data
List the variables available in a given dataset and vintage via variables.json
List the geographic levels supported by a dataset via geography.json
Browse variable groups for ACS detailed and subject tables
Run dataset queries scoped by variable list and geography filter via /data/{vintage}/{dataset}
Use Cases
Patterns agents use Census Data API for, with concrete tasks.
★ Demographic Lookup for Geographic Analysis
Civic-tech teams, researchers, and data agents query ACS variables — population, age, race, income — for a chosen geography to feed dashboards or reports. The agent first lists variables for the dataset, then queries /data/{vintage}/{dataset} with a variable list and a geographic filter such as `for=county:*&in=state:06`.
GET /data/2022/acs/acs5 with get=B01003_001E (total population) and for=county:* in state 06 to return California county populations
Variable Discovery for Reporting
A reporting workflow needs to pick the right Census variable codes for a question like 'median household income by tract'. An agent queries variables.json for the target dataset, filters by label, and returns the variable code and concept. This eliminates the manual code lookup against Census documentation.
GET /data/2022/acs/acs5/variables.json and search for 'Median household income' to return the matching variable code and concept
Geography-Aware Address Enrichment
Companies enriching customer addresses with demographic context use the Census API to fetch tract or ZIP-code-level statistics for the geocoded address. The geography.json endpoint confirms which levels the dataset supports, and the data query returns the requested variables for that geography.
GET /data/2022/acs/acs5/geography.json to confirm tract-level support, then query variables for tract 06037201001
AI Agent Integration via Jentic
A research agent uses Jentic to discover Census datasets, load schemas for the variables and data endpoints, and execute calls without holding the API key directly. The agent can chain Census lookups with cBioPortal or CDC ReportStream context for population-normalised public-health analyses.
Use Jentic to search 'query Census ACS data', load the schema for /data/{vintage}/{dataset}, and execute against acs5 for the requested county
Key Endpoints
5 endpoints — jentic publishes the only available openapi specification for the u.
METHOD
PATH
DESCRIPTION
GET
/data
List all available Census datasets
GET
/data/{vintage}/{dataset}
Query a specific Census dataset
GET
/data/{vintage}/{dataset}/variables.json
List variables for a dataset
GET
/data/{vintage}/{dataset}/geography.json
List geographies for a dataset
GET
/data/{vintage}/{dataset}/groups.json
List variable groups
GET
/data
List all available Census datasets
GET
/data/{vintage}/{dataset}
Query a specific Census dataset
GET
/data/{vintage}/{dataset}/variables.json
List variables for a dataset
GET
/data/{vintage}/{dataset}/geography.json
List geographies for a dataset
GET
/data/{vintage}/{dataset}/groups.json
List variable groups
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Census API keys are stored encrypted in the Jentic vault and appended to each request as the `key` query parameter at execution time. Agents never hold the raw key value.
Intent-based discovery
Agents search Jentic by intent (e.g., 'query Census ACS data') and Jentic returns the /data and variables.json operations with their input schemas, so the agent doesn't need to navigate Census documentation.
Time to first call
Direct Census integration: 1-2 days mapping dataset, variable, and geography parameters and handling JSON-array responses. Through Jentic: under 1 hour — search, load schema, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Census Data API through Jentic.
Why is there no official OpenAPI spec for the Census Data API?
The Census Bureau publishes documentation pages but not a structured OpenAPI artifact. Jentic generates and maintains this spec so that AI agents and developers can call Census Data API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.
What authentication does the Census Data API use?
Census uses an API key passed as the `key` query parameter. Keys are issued for free at api.census.gov/data/key_signup.html and are required above a small unauthenticated threshold. Through Jentic the key is stored in the encrypted vault and appended at execution time.
Can I query American Community Survey data with this API?
Yes. GET /data/{vintage}/{dataset} with dataset paths like acs/acs5 or acs/acs1 runs ACS queries. Use the variables.json endpoint to find the right variable codes and geography.json to find supported geographic levels.
What are the rate limits for the Census Data API?
The Census Bureau allows up to 500 calls per IP address per day without a key, with no public hard cap once a key is registered. Throttle bulk pulls and back off on 429 responses; very large variable-by-tract queries should be batched.
How do I run an ACS query through Jentic?
Search Jentic for 'query Census ACS data', load the schema for GET /data/{vintage}/{dataset}, and execute with the variable list in the get parameter and the geography filter in for/in. The Census key stays in the Jentic vault.
Is the Census Data API free?
Yes. The Census Data API is free to use. Keys are also free; they exist to track and lift the unauthenticated rate cap.
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