Free APIs
Free Government & open data APIs
| API | Free tier | Auth | Docs |
|---|---|---|---|
| api.data.gov Shared key for many US federal APIs Catch: Default hourly limit per key | Free key: default 1,000 requests/hour | API key | docs |
| US Census Bureau API Population, economic and demographic data Catch: Heavy use requires a free API key | Free; key recommended | API key | docs |
| World Bank Indicators API Development indicators for countries over decades Catch: Pagination limits per request | Free, no key | No key | docs |
| Congress.gov API Bills, members, committees and votes Catch: Hourly cap | Free key: 5,000 requests/hour | API key | docs |
| OpenFEC API US campaign finance data Catch: Rate limit per key | Free key with hourly rate limit | API key | docs |
| Treasury FiscalData API US debt, spending, exchange rates and more Catch: Fair-use limits | Free, no key | No key | docs |
| USAspending API US federal contracts, grants and awards Catch: Large queries may time out | Free, no key | No key | docs |
| BLS Public Data API US labor statistics and CPI series Catch: Unregistered use has lower daily limits | Free; registered key gets higher limits | API key | docs |
| NOAA Climate Data Online API Historical US weather and climate records Catch: Token via email | Free token: 5 requests/second, 10,000 requests/day | API key | docs |
| UK Police Data API UK crime, outcomes and neighborhood data Catch: Rate limited | Free, no key; 15 requests/second | No key | docs |
| Companies House API UK company register data Catch: Rate limit per key | Free key: 600 requests per 5 minutes | API key | docs |
| Socrata Open Data API (SODA) Open data portals for many US cities and agencies Catch: Throttled without an app token | Free; app token raises limits | No key | docs |
FAQ
What is the best free government & open data API?+
api.data.gov, US Census Bureau API, World Bank Indicators API are good places to start. Compare the free tiers and catches in the table; they differ mostly in limits and whether commercial use is allowed.
Is there a government & open data API without an API key?+
Yes: World Bank Indicators API, Treasury FiscalData API, USAspending API, UK Police Data API, Socrata Open Data API (SODA) work without a key.
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