Census Bureau integrations and automation

The Census Bureau Data API is public statistics rather than a business account: population, income, housing, commuting and business counts for the United States, from states down to counties, tracts and block groups. People automate it to keep a market sizing sheet current, enrich a list of store locations with neighbourhood demographics, or refresh a dashboard when a new data year is released. There is nothing to watch for in real time, so these are scheduled or on-demand workflows.

Queries follow one pattern: a dataset path such as /data/2023/acs/acs5, a get parameter naming variables, and for and in parameters naming geography, for example every county in one state. Variables are codes like B19013_001E (median household income) and come with margin-of-error companions ending in M. Each dataset publishes a variables list and the geographies it supports, and the most common mistake is mixing variables from one dataset into a query for another. The response is a table whose first row holds the column names.

Choosing the survey is the real decision. The American Community Survey 5-year estimates cover every geography, including small ones, but average five years of data. The 1-year estimates are more current but are published only for areas with 65,000 or more people. The decennial census gives exact counts on fewer topics. Estimates also carry margins of error that can be large for small areas; a workflow that ranks tracts by income should keep the margin column rather than presenting the estimate as exact.

An API key is free from the Census Bureau. The documentation states that a key is needed beyond 500 queries per IP address per day, and because a hosted runtime may share addresses, include your own key from the start. Geography is identified by FIPS codes, so joining census figures to your own address list usually needs a geocoding step that returns the state, county and tract codes first.