OpenTrials API

opentrials · Data

Data No Auth Free & Open open_data

OpenTrials API API

Authentication

No authentication requiredFree to use with no key needed.

Sample Requests

GET listDocuments

Returns documents

https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents?page=1&per_page=20

Hover any highlighted part to learn what it does

curl -X GET "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents?page=1&per_page=20"

import requests
params = {
    "page": "1",
    "per_page": "20"
}
response = requests.get(
    "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents",
    params=params,
)
print(response.json())

const url = new URL('https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents');
url.searchParams.set('page', '1');
url.searchParams.set('per_page', '20');

const response = await fetch(url); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
)

func main() {
	baseURL, _ := url.Parse("https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents")
	q := baseURL.Query()
	q.Set("page", "1")
	q.Set("per_page", "20")
	baseURL.RawQuery = q.Encode()
	targetURL := baseURL.String()
	req, _ := http.NewRequest("GET", targetURL, nil)

	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

require "net/http"
require "json"

uri = URI("https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents")
uri.query = URI.encode_www_form({
  "page" => "1",
  "per_page" => "20"
})

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"

req = Net::HTTP::Get.new(uri)

res = http.request(req)
puts JSON.parse(res.body)

<?php
$url = "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/documents?" . http_build_query([
    "page" => "1",
    "per_page" => "20"
]);
$opts = ["http" => [
    "method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

GET listFDAApplications

Returns FDA applications

https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications?page=1&per_page=20

Hover any highlighted part to learn what it does

curl -X GET "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications?page=1&per_page=20"

import requests
params = {
    "page": "1",
    "per_page": "20"
}
response = requests.get(
    "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications",
    params=params,
)
print(response.json())

const url = new URL('https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications');
url.searchParams.set('page', '1');
url.searchParams.set('per_page', '20');

const response = await fetch(url); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
)

func main() {
	baseURL, _ := url.Parse("https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications")
	q := baseURL.Query()
	q.Set("page", "1")
	q.Set("per_page", "20")
	baseURL.RawQuery = q.Encode()
	targetURL := baseURL.String()
	req, _ := http.NewRequest("GET", targetURL, nil)

	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

require "net/http"
require "json"

uri = URI("https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications")
uri.query = URI.encode_www_form({
  "page" => "1",
  "per_page" => "20"
})

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"

req = Net::HTTP::Get.new(uri)

res = http.request(req)
puts JSON.parse(res.body)

<?php
$url = "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/fda_applications?" . http_build_query([
    "page" => "1",
    "per_page" => "20"
]);
$opts = ["http" => [
    "method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

GET searchTrials

Returns trials based on a search query. By default, it'll search in all of a trial's attributes. - `q` is a [ElasticSearch query string](https://www.elastic.co/guide/en/elasticsearch/reference/2.3/query-dsl-query-string-query.html#query-string-syntax) (e.g. `public_title:(depressive OR depression)`)

https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search?q=test&page=1&per_page=20

Hover any highlighted part to learn what it does

curl -X GET "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search?q=test&page=1&per_page=20"

import requests
params = {
    "q": "test",
    "page": "1",
    "per_page": "20"
}
response = requests.get(
    "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search",
    params=params,
)
print(response.json())

const url = new URL('https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search');
url.searchParams.set('q', 'test');
url.searchParams.set('page', '1');
url.searchParams.set('per_page', '20');

const response = await fetch(url); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
)

func main() {
	baseURL, _ := url.Parse("https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search")
	q := baseURL.Query()
	q.Set("q", "test")
	q.Set("page", "1")
	q.Set("per_page", "20")
	baseURL.RawQuery = q.Encode()
	targetURL := baseURL.String()
	req, _ := http.NewRequest("GET", targetURL, nil)

	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

require "net/http"
require "json"

uri = URI("https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search")
uri.query = URI.encode_www_form({
  "q" => "test",
  "page" => "1",
  "per_page" => "20"
})

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"

req = Net::HTTP::Get.new(uri)

res = http.request(req)
puts JSON.parse(res.body)

<?php
$url = "https://api.apis.guru/v2/specs/opentrials.local/0.0.1/search?" . http_build_query([
    "q" => "test",
    "page" => "1",
    "per_page" => "20"
]);
$opts = ["http" => [
    "method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

Postman Setup Guide

Get Postman ↗

See official documentation for authentication and setup.

What can you build with OpenTrials API?

OpenTrials API is a Data API. Developers commonly use data APIs for:

enriching your app with third-party datasets
building data pipelines and ETL workflows
querying and searching large datasets
powering research, analysis, and reporting tools
syncing reference data into your own systems

No authentication required. This API is open — no signup or key needed. Ideal for quick prototypes and public-facing features. OpenTrials API is free to use, making it a low-risk choice to experiment with.

New to APIs? Read our beginner's guide

Open documentation ↗