Clinical Trials (ClinicalTrials.gov)
ClinicalTrials.gov API v2 from the U.S. National Library of Medicine, reshaped into compact records. Personal contact details are never returned. Every response credits the source and gives the date the data were last processed.
- cost
- Free tier 3 of 4 free, 1 with 3 free calls a day
- after that
- from $0.002 / call · card or USDC
- endpoints
- 4
No signup needed over MCP: 100 free calls a day, or 500 with a free key.
Search clinical trials Free
Find studies by condition, intervention (drug/device), location, sponsor or free text, optionally filtered by status and phase.
- cost
- Free then $0.003 / call
- MCP tool
- clinical-trials__search
- method
- GET
Free up to 100 calls a day over MCP (500 with a free key), then $0.003 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/clinical-trials/search
| Param | Type | Description |
|---|---|---|
| condition? | string | Condition or disease, e.g. "type 2 diabetes" |
| intervention? | string | Drug, device or procedure |
| location? | string | City, region or country |
| sponsor? | string | Sponsor or collaborator |
| q? | string | Free-text search across the record |
| status? | string | Comma-separated: RECRUITING, NOT_YET_RECRUITING, ACTIVE_NOT_RECRUITING, COMPLETED, TERMINATED… |
| phase? | string | 1, 2, 3, 4, EARLY_PHASE1 or NA |
| limit? | integer | Results per page, 1-50 (default 20) |
| page_token? | string | next_page_token from a previous response |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/clinical-trials/search" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/clinical-trials/search"
by fourzerotwo
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Study by NCT number Free
One study: title, status, phase, conditions, interventions, sponsor, enrolment, dates, eligibility basics, primary outcomes, countries, whether results are posted.
- cost
- Free then $0.002 / call
- MCP tool
- clinical-trials__study
- method
- GET
Free up to 100 calls a day over MCP (500 with a free key), then $0.002 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/clinical-trials/study
| Param | Type | Description |
|---|---|---|
| nct_id | string | NCT number |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/clinical-trials/study?nct_id=NCT04368728" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/clinical-trials/study?nct_id=NCT04368728"
by fourzerotwo
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Recruiting trials near a place Free
Studies recruiting (or about to) for a condition in a city, region or country, with the matching trial sites.
- cost
- Free then $0.003 / call
- MCP tool
- clinical-trials__recruiting
- method
- GET
Free up to 100 calls a day over MCP (500 with a free key), then $0.003 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/clinical-trials/recruiting
| Param | Type | Description |
|---|---|---|
| condition | string | Condition or disease |
| location | string | City, region or country |
| limit? | integer | Results per page, 1-50 (default 20) |
| page_token? | string | next_page_token from a previous response |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/clinical-trials/recruiting?condition=breast%20cancer&location=London" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/clinical-trials/recruiting?condition=breast%20cancer&location=London"
by fourzerotwo
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Trial counts by status 3 free / day
How many registered studies for a condition are recruiting, active, completed, terminated or withdrawn.
- cost
- 3 free / day then $0.003 / call
- MCP tool
- clinical-trials__stats
- method
- GET
3 free calls a day, then $0.003 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/clinical-trials/stats
| Param | Type | Description |
|---|---|---|
| condition | string | Condition or disease |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/clinical-trials/stats?condition=migraine" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/clinical-trials/stats?condition=migraine"
by fourzerotwo
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Source: ClinicalTrials.gov, U.S. National Library of Medicine (US Government, free of charge). Reformatted by fourzerotwo; no endorsement implied.