ClinicalTrials.gov's v2 API at https://clinicaltrials.gov/api/v2 searches the US National Library of Medicine's registry of clinical studies worldwide.
None — no key, no signup. Every example runs as-is.
Full reference: https://clinicaltrials.gov/data-api/api
query.cond matches conditions; fields trims each study.
curl "https://clinicaltrials.gov/api/v2/studies?query.cond=diabetes&filter.overallStatus=RECRUITING&pageSize=2&fields=NCTId,BriefTitle,OverallStatus"{
"studies": [
{
"protocolSection": {
"identificationModule": {
"nctId": "NCT05390892",
"briefTitle": "PREvention of CardIovascular and DiabEtic kidNey Disease in Type 2 Diabetes"
},
"statusModule": {
"overallStatus": "RECRUITING"
}
}
},
{
"protocolSection": {
"identificationModule": {
"nctId": "NCT07518407",
"briefTitle": "Dietary Insights and Nutritional Education in Adults on GLP-1 Therapy"
},
"statusModule": {
"overallStatus": "RECRUITING"
}
}
}
],
"nextPageToken": "ZVNj7o2Elu8o3lpwWM-j4bbumpOQJJxsbfWk0A"
}curl "https://clinicaltrials.gov/api/v2/studies/NCT04368728?fields=NCTId,BriefTitle,OverallStatus,Phase"{
"protocolSection": {
"identificationModule": {
"nctId": "NCT04368728",
"briefTitle": "Study to Describe the Safety, Tolerability, Immunogenicity, and Efficacy of RNA Vaccine Candidates Against COVID-19 in Healthy Individuals"
},
"statusModule": {
"overallStatus": "COMPLETED"
},
"designModule": {
"phases": [
"PHASE2",
"PHASE3"
]
}
}
}