### GET /search (Location)

Source: https://clinicaltrials.gov/data-api/about-api/search-areas

Search for clinical trials based on location terms.

```APIDOC
## GET /search?query.locn=[value]

### Description
Default search area for the 'Location terms' input field.

### Query Parameters
- **query.locn** (text) - Required - The location search query.

### Data Fields
- **LocationCity** (GeoName) - Weight: 0.95
- **LocationState** (GeoName) - Weight: 0.95
- **LocationCountry** (text) - Weight: 0.95
- **LocationFacility** (text) - Weight: 0.95
- **LocationZip** (text) - Weight: 0.35
```

--------------------------------

### GET /api/info/api_vrs

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Returns the current version number of the ClinicalTrials.gov API.

```APIDOC
## GET /api/info/api_vrs

### Description
Returns the current version number of the ClinicalTrials.gov API. The version changes when the study structure or API features change.

### Method
GET

### Endpoint
/api/info/api_vrs
```

--------------------------------

### GET /search (Sponsor)

Source: https://clinicaltrials.gov/data-api/about-api/search-areas

Search for clinical trials based on sponsor or collaborator information.

```APIDOC
## GET /search?query.spons=[value]

### Description
Default search area for the 'Sponsor / collaborator' input field.

### Query Parameters
- **query.spons** (text) - Required - The sponsor search query.

### Data Fields
- **LeadSponsorName** (text) - Weight: 1
- **CollaboratorName** (text) - Weight: 0.9
- **OrgFullName** (text) - Weight: 0.6
```

--------------------------------

### GET /search (Intervention)

Source: https://clinicaltrials.gov/data-api/about-api/search-areas

Search for clinical trials based on intervention or treatment criteria.

```APIDOC
## GET /search?query.intr=[value]

### Description
Default search area for the 'Intervention / treatment' input field.

### Query Parameters
- **query.intr** (text) - Required - The intervention search query.

### Data Fields
- **InterventionName** (text) - Weight: 0.95
- **InterventionType** (enum) - Weight: 0.85
- **ArmGroupType** (enum) - Weight: 0.85
- **InterventionOtherName** (text) - Weight: 0.75
- **BriefTitle** (text) - Weight: 0.65
- **OfficialTitle** (text) - Weight: 0.6
- **ArmGroupLabel** (text) - Weight: 0.5
- **InterventionMeshTerm** (text) - Weight: 0.5
- **Keyword** (text) - Weight: 0.5
- **InterventionAncestorTerm** (text) - Weight: 0.4
- **InterventionDescription** (markup) - Weight: 0.4
- **ArmGroupDescription** (markup) - Weight: 0.4
```

--------------------------------

### Download Matching Studies

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Download a Zip archive containing studies that match specified search criteria, in XML format. The new endpoint `/api/v2/studies` allows for more structured searching. Legacy endpoint support requires constructing a search expression.

```APIDOC
## GET /api/v2/studies

### Description
Retrieves a list of studies matching the specified search criteria. The results are returned in JSON format. Search options can be provided as query parameters.

### Method
GET

### Endpoint
/api/v2/studies

### Parameters
#### Query Parameters
- **fields** (string) - Optional - Comma-separated list of data elements to include.
- **sort** (string) - Optional - Field to sort the results by.
- **order** (string) - Optional - Order of sorting ('asc' or 'desc').
- **maxResults** (integer) - Optional - Maximum number of results to return.
- **fromRecord** (integer) - Optional - Starting record number for pagination.
- **query** (string) - Optional - A structured query string for advanced searching.

### Request Example
```json
{
  "example": "GET /api/v2/studies?query=AREA[ConditionSearch]cancer AND AREA[BasicSearch]treatment&fields=NCTId,Title"
}
```

### Response
#### Success Response (200)
- **studies** (array) - An array of study objects matching the search criteria.

#### Response Example
```json
{
  "example": "{\"studies\": [ { \"NCTId\": \"NCT000001\", \"Title\": \"Example Study Title\" } ]}"
}
```

### Legacy Endpoint Support
`GET /ct2/download_studies`
```

--------------------------------

### Download All API XML Data

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Download a Zip archive containing all full study data in XML format. The new endpoint provides this data in JSON format. Legacy endpoint support for XML format is also available.

```APIDOC
## GET /api/v2/studies/download?format=json.zip

### Description
Downloads a Zip archive containing all full study data in JSON format. The schema for individual JSON files matches the `/api/v2/studies/{nctId}` endpoint response.

### Method
GET

### Endpoint
/api/v2/studies/download

### Parameters
#### Query Parameters
- **format** (string) - Required - Specifies the output format, should be 'json.zip'.

### Request Example
```json
{
  "example": "GET /api/v2/studies/download?format=json.zip"
}
```

### Response
#### Success Response (200)
- **file** (zip) - A zip archive containing full study data in JSON format.

### Legacy Endpoint Support
`GET /AllAPIXML.zip`
```

--------------------------------

### GET /api/info/data_vrs

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Retrieves the date when the ClinicalTrials.gov dataset was last posted.

```APIDOC
## GET /api/info/data_vrs

### Description
Returns the date when the ClinicalTrials.gov dataset was posted.

### Method
GET

### Endpoint
/api/info/data_vrs

### Response
#### Success Response (200)
- **dataTimestamp** (string) - The date and time the dataset was posted.
```

--------------------------------

### Download All Public Data

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Download a Zip archive containing all public study data in JSON format. The JSON schema for each file is consistent with the response of the `/api/v2/studies/{nctId}` endpoint. Legacy endpoint support for XML format is also available.

```APIDOC
## GET /api/v2/studies/download?format=json.zip

### Description
Downloads a Zip archive containing all public study data in JSON format. The schema for individual JSON files matches the `/api/v2/studies/{nctId}` endpoint response.

### Method
GET

### Endpoint
/api/v2/studies/download

### Parameters
#### Query Parameters
- **format** (string) - Required - Specifies the output format, should be 'json.zip'.

### Request Example
```json
{
  "example": "GET /api/v2/studies/download?format=json.zip"
}
```

### Response
#### Success Response (200)
- **file** (zip) - A zip archive containing study data in JSON format.

### Legacy Endpoint Support
`GET /AllPublicXML.zip`
```

--------------------------------

### GET /search (Outcome)

Source: https://clinicaltrials.gov/data-api/about-api/search-areas

Search for clinical trials based on outcome measures.

```APIDOC
## GET /search?query.outc=[value]

### Description
Default search area for the 'Outcome measure' input field.

### Query Parameters
- **query.outc** (text) - Required - The outcome measure search query.

### Data Fields
- **PrimaryOutcomeMeasure** (text) - Weight: 0.9
- **SecondaryOutcomeMeasure** (text) - Weight: 0.8
- **PrimaryOutcomeDescription** (markup) - Weight: 0.6
- **SecondaryOutcomeDescription** (markup) - Weight: 0.5
- **OtherOutcomeMeasure** (text) - Weight: 0.4
- **OutcomeMeasureTitle** (text) - Weight: 0.4
- **OtherOutcomeDescription** (markup) - Weight: 0.3
- **OutcomeMeasureDescription** (markup) - Weight: 0.3
- **OutcomeMeasurePopulationDescription** (markup) - Weight: 0.3
```

--------------------------------

### GET /api/query/study_fields

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Retrieves specific fields for a large set of study records.

```APIDOC
## GET /api/query/study_fields

### Description
Returns values from selected API fields for a large set of study records.

### Method
GET

### Endpoint
/api/query/study_fields

### Parameters
#### Query Parameters
- **fields** (string) - Required - The specific fields to return for the study records.
- **expr** (string) - Optional - The search expression used to filter studies.

### Response
#### Success Response (200)
- **format** (CSV/JSON) - The requested fields for the study records.
```

--------------------------------

### Intervention Browse Module Fields

Source: https://clinicaltrials.gov/data-api/about-api/study-data-structure

Details regarding the intervention browse module, including ancestors, leaf topics, and branch topics.

```APIDOC
## Intervention Browse Module Fields

### Description
Provides access to MeSH hierarchy data for interventions, including ancestor terms, leaf topics, and branch topics.

### Fields
- **InterventionAncestor** (Mesh[]) - Ancestor terms of Intervention MeSH terms.
- **InterventionAncestorId** (text) - MeSH ID for the ancestor.
- **InterventionAncestorTerm** (text) - MeSH Heading for the ancestor.
- **NumInterventionAncestors** (short) - Count of intervention ancestor terms.
- **InterventionBrowseLeaf** (BrowseLeaf[]) - Leaf browsing topics for the intervention.
- **InterventionBrowseLeafId** (text) - ID for the leaf topic.
- **InterventionBrowseLeafName** (text) - Name of the leaf topic.
- **InterventionBrowseLeafAsFound** (text) - Normalized term used to find the topic.
- **InterventionBrowseLeafRelevance** (enum) - Relevance level of the leaf topic.
- **NumInterventionBrowseLeafs** (short) - Count of intervention leaf topics.
- **InterventionBrowseBranch** (BrowseBranch[]) - Branch browsing topics for the intervention.
- **InterventionBrowseBranchAbbrev** (text) - Short name of the branch topic.
- **InterventionBrowseBranchName** (text) - Name of the branch topic.
- **NumInterventionBrowseBranches** (short) - Count of intervention branch topics.
```

--------------------------------

### References Module

Source: https://clinicaltrials.gov/data-api/about-api/study-data-structure

Details regarding references and citations related to a study protocol.

```APIDOC
## ReferencesModule

### Index Field
protocolSection.referencesModule

### Data Type
ReferencesModule

### Definition
References(https://clinicaltrials.gov/policy/protocol-definitions#References)

## Reference - Citations to publications related to the protocol

### Index Field
protocolSection.referencesModule.references

### Data Type
Reference[]

### Definition
Citations(https://clinicaltrials.gov/policy/protocol-definitions#RefCitations)

## ReferencePMID - PubMed Identifier

### Index Field
protocolSection.referencesModule.references.pmid

### Data Type
text (stats(https://clinicaltrials.gov/api/v2/stats/field/values?fields=ReferencePMID))

### Definition
PubMed Identifier(https://clinicaltrials.gov/policy/protocol-definitions#PubMedId)

## ReferenceType - Reference Type

### Index Field
protocolSection.referencesModule.references.type

### Data Type
enum ReferenceType(https://clinicaltrials.gov#enum-ReferenceType) (stats(https://clinicaltrials.gov/api/v2/stats/field/values?fields=ReferenceType))

### Definition
Results Reference(https://clinicaltrials.gov/policy/protocol-definitions#IsResultsRef)

## ReferenceCitation - Reference Citation

### Index Field
protocolSection.referencesModule.references.citation

### Data Type
text ✓ (stats(https://clinicaltrials.gov/api/v2/stats/field/values?fields=ReferenceCitation))

### Definition
Citation(https://clinicaltrials.gov/policy/protocol-definitions#Citation)

## Retraction

### Index Field
protocolSection.referencesModule.references.retractions

### Data Type
Retraction[]

## RetractionPMID - PMID for Publication Retraction

### Index Field
protocolSection.referencesModule.references.retractions.pmid

### Data Type
text (stats(https://clinicaltrials.gov/api/v2/stats/field/values?fields=RetractionPMID))

### Description
PMID for publication retraction

## RetractionSource

### Index Field
protocolSection.referencesModule.references.retractions.source

### Data Type
text ✓ (stats(https://clinicaltrials.gov/api/v2/stats/field/values?fields=RetractionSource))
```

--------------------------------

### GET /api/query/field_values

Source: https://clinicaltrials.gov/data-api/about-api/api-migration

Retrieves all values found in a single API field for all study records.

```APIDOC
## GET /api/query/field_values

### Description
Returns all values found in a single API field for all study records.

### Method
GET

### Endpoint
/api/query/field_values

### Response
#### Success Response (200)
- **data** (array) - A list of all values found in the specified field.
```