ClinicalTrials.gov

US clinical trial registry search

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NIH ClinicalTrials.gov v2 API returns structured study records — conditions, interventions, locations and status. Public JSON with no API key on read endpoints.

HOW IT'S SCORED ⓘ
Status badge · for your READMEshipapis health badge: — · unmonitored
ON PROBE SCHEDULE

We probe a documented GET and expect 2xx JSON — full uptime and health score. Open provider docs ↗

Uptime historystarts after first probe

On our probe schedule. Uptime charts appear after the first check lands.

Example responsefrom provider docs — not verified by us
GET https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&pageSize=1

{
  "studies": [
    {
      "protocolSection": {
        "identificationModule": {
          "nctId": "NCT02076503",
          "orgStudyIdInfo": {
            "id": "2013/1513"
          },
          "organization": {
            "fullName": "St. Olavs Hospital",
            "class": "OTHER"
          },
          "briefTitle": "Pre-operative PET-MR of High Risk Prostate Cancer Patients for Assessment of Cancer Aggressiveness and Lymph Node Status",
          "officialTitle": "Pre-operative PET-MR of High Risk Prostate Cancer Patients for Assessment of Cancer Aggressiveness and Lymph Node Status"
        },
        "statusModule": {
          "statusVerifiedDate": "2018-01",
          "overallStatus": "COMPLETED",
          "expandedAccessInfo": {
            "hasExpandedAccess": false
          },
          "startDateStruct": {
            "date": "2014-04",
            "type": "ACTUAL"
          },
          "primaryCompletionDateStruct": {
            "date": "2015-05",
            "type": "ACTUAL"
          },
          "completionDateStruct": {
            "date": "2015-05",
            "type": "ACTUAL"
          },
          "studyFirstSubmitDate": "2014-02-10",
          "studyFirstSubmitQcDate": "2014-02-27"
        },
        "sponsorCollaboratorsModule": {
          "responsibleParty": {
            "type": "SPONSOR"
          },
          "leadSponsor": {
            "name": "St. Olavs Hospital",
            "class": "OTHER"
          },
          "collaborators": [
            {
              "name": "Norwegian University of Science and Technology",
              "class": "OTHER"
            },
            {
              "name": "Norwegian Cancer Society",
              "class": "OTHER"
            }
          ]
        },
        "oversightModule": {
          "oversightHasDmc": false,
          "isFdaRegulatedDrug": false,
          "isFdaRegulatedDevice": false
        },
        "descriptionModule": {
          "briefSummary": "Prostate cancer is the most frequent cancer in Norwegian men. For optimal treatment, accurate staging of the disease at the time point of diagnosis is important. The objective of this study is to evaluate the diagnostic potential of a combined PET/MR examination for risk assessment and detection of lymph node metastases. The overall aim of the project is to improve the investigators ability to provide individually tailored treatment to prostate cancer patients.\n\nThe study will include 32 men with high-risk prostate cancer, who are eligible for radical prostatectomy. Informed consent is a requirement for inclusion in the study."
        },
        "conditionsModule": {
          "conditions": [
            "Prostatic Neoplasms"
          ],
          "keywords": [
            "Neoplasm Staging",
            "Positron-Emission Tomography"
          ]
        },
        "designModule": {
          "studyType": "INTERVENTIONAL",
          "phases": [
            "NA"
          ],
          "designInfo": {
            "allocation": "NA",
            "interventionModel": "SINGLE_GROUP",
            "primaryPurpose": "DIAGNOSTIC",
            "maskingInfo": {
              "masking": "NONE"
            }
          },
          "enrollmentInfo": {
            "count": 28,
            "type": "ACTUAL"
          }
        },
        "armsInterventionsModule": {
          "armGroups": [
            {
              "label": "PET-MR 18F-FACBC",
              "type": "EXPERIMENTAL",
              "interventionNames": [
                "Procedure: PET-MR 18f-FACBC",
                "Procedure: histology (gold standard)"
              ]
            }
          ],
          "interventions": [
            {
              "type": "PROCEDURE",
              "name": "PET-MR 18f-FACBC",
              "armGroupLabels": [
                "PET-MR 18F-FACBC"
              ]
            },
            {
              "type": "PROCEDURE",
              "name": "histology (gold standard)",
              "description": "histopathological classification of co-located dissected lymph nodes",
              "armGroupLabels": [
                "PET-MR 18F-FACBC"
              ]
            }
          ]
        }
      },
      "derivedSection": {
        "miscInfoModule": {
          "versionHolder": "2026-07-02"
        },
        "conditionBrowseModule": {
          "meshes": [
            {
              "id": "D011471",
              "term": "Prostatic Neoplasms"
            }
          ],
          "ancestors": [
            {
              "id": "D005834",
              "term": "Genital Neoplasms, Male"
            },
            {
              "id": "D014565",
              "term": "Urogenital Neoplasms"
            }
          ]
        }
      },
      "hasResults": false
    }
  ],
  "nextPageToken": "ZVNj7o2Elu8o3lp3D4Czt-numpOQJJxsaQ"
}
Call itcurl · fetch · python
curl "https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&pageSize=1"
const res = await fetch("https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&pageSize=1");
const data = await res.json();
console.log(data);
import requests

res = requests.get("https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&pageSize=1")
print(res.json())
Endpoints · 3On scheduleFULL DOCS ↗
On schedule — GET /studies?query.cond=cancer&pageSize=1 awaits first probe
GET/studies?query.cond=cancer&pageSize=1PROBED

US clinical trial registry search

GET/studies?limit=5

Studies — documented GET route.

GET/studies?page=1

Studies — documented GET route.

Machine-readable spec

We probe a documented GET and expect 2xx JSON — full uptime and health score. Export includes every documented route below.

Response-shape history

Not tracked yet. Shape-change history starts once this API joins our probe schedule.

ClinicalTrials.gov: common questions

Is ClinicalTrials.gov free to use?

Yes — ClinicalTrials.gov is a free health & food API. Free tier: Free — limits not published. Whether the free tier allows commercial use is unclear — check the provider docs.

Does ClinicalTrials.gov need an API key?

No — ClinicalTrials.gov needs no API key or signup. You can call it straight away; rate limits still apply (Unpublished).

Can I call ClinicalTrials.gov from the browser?

Yes — ClinicalTrials.gov returns CORS headers over HTTPS, so front-end code can fetch it directly with no backend proxy. Use the fetch snippet on this page, or hit "Run live" to try it now.

Is ClinicalTrials.gov up right now?

ClinicalTrials.gov is catalogued but not yet on our probe schedule, so we don't publish a live status for it. Check the provider's own status page or docs for its current state.