# Free Health Data APIs

Page: https://free-web-services.com/web-services/open-data/health/

Health data APIs give public-health statistics, clinical trials, drug names and safety data, and food hygiene ratings from bodies such as the WHO, the US National Library of Medicine, the FDA and the CDC. They are for information and research, not medical advice.

## Services

| Service | API key | Formats | Free use |
|---|---|---|---|
| [CDC Open Data API (data.cdc.gov)](https://free-web-services.com/web-services/open-data/health/cdc-open-data-api.md) | Not needed | JSON, CSV | Free, no key needed; a free app token raises the rate limit. |
| [ClinicalTrials.gov API](https://free-web-services.com/web-services/open-data/health/clinicaltrials-gov-api.md) | Not needed | JSON | Free, no key needed. |
| [Food Hygiene Rating API (FSA)](https://free-web-services.com/web-services/open-data/health/food-hygiene-rating-api.md) | Not needed | JSON, XML | Free, no key needed. |
| [openFDA](https://free-web-services.com/web-services/open-data/health/openfda.md) | Not needed | JSON | Free; works without a key, and a free API key raises the daily limit. |
| [RxNorm API (RxNav)](https://free-web-services.com/web-services/open-data/health/rxnorm-api.md) | Not needed | JSON, XML | Free, no key needed. |
| [WHO Global Health Observatory API](https://free-web-services.com/web-services/open-data/health/who-gho-api.md) | Not needed | JSON | Free, no key needed. |

## Questions

**Which free health data APIs work without an API key?**  
CDC Open Data API (data.cdc.gov), ClinicalTrials.gov API, Food Hygiene Rating API (FSA), openFDA, RxNorm API (RxNav) and WHO Global Health Observatory API work without a key, according to their documentation. Most keyless services ask you to keep the number of requests reasonable, and some ask for a User-Agent that names your app.

**Are these health data APIs really free?**  
The services here can be used without paying, at least on a free plan or free tier, often with limits such as a number of requests per day or non-commercial use only. The table above quotes what each service says about its free use; check the provider's own terms before you rely on it.

**How up to date is this list?**  
The address of every service is checked about once a week, and services that stop working or stop being free are removed. This list last changed on November 8th, 2026.