# Count participants

POST https://api.prolific.com/api/v1/eligibility-count/
Content-Type: application/json

Count how many participants meet all the given filters.
Only participants that pass **every one** of the filters are counted.
Zero means that there are less than 25 participants. We do not show lower numbers to protect the privacy of the participants.

To see a list of filters that may be passed to this endpoint, see the documentation for filters.

Reference: https://beta-docs.prolific.com/api-reference/filters/get-eligible-count

## OpenAPI Specification

```yaml
openapi: 3.1.1
info:
  title: Count participants
  version: endpoint_filters.GetEligibleCount
paths:
  /api/v1/eligibility-count/:
    post:
      operationId: get-eligible-count
      summary: Count participants
      description: >-
        Count how many participants meet all the given filters.

        Only participants that pass **every one** of the filters are counted.

        Zero means that there are less than 25 participants. We do not show
        lower numbers to protect the privacy of the participants.


        To see a list of filters that may be passed to this endpoint, see the
        documentation for filters.
      tags:
        - - subpackage_filters
      parameters:
        - name: Authorization
          in: header
          description: Header authentication of the form `undefined <token>`
          required: true
          schema:
            type: string
      responses:
        '200':
          description: Count
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RequirementsCount'
        '400':
          description: Error
          content: {}
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/RequirementsCountRequest'
components:
  schemas:
    SelectFilter:
      type: object
      properties:
        filter_id:
          type: string
          description: ID of the "select" type filter.
        selected_values:
          type: array
          items:
            type: string
          description: >-
            This schema applies for filters of the `select` type, as defined in
            the [filter list
            response](\#tag/Filters/paths/~1api~1v1~1filters~1/get).


            Array of IDs matching the response IDs, from the `select` filter's
            `choices` (see response linked above).


            String format should match the `data_type` of the `select` filter's
            `choices` (see response linked above).
        weightings:
          type: object
          additionalProperties:
            type: number
            format: double
          description: >-
            Ratios to control the distribution of participants across the
            selected values.


            Integer percentages, floats, and exact quantities are valid inputs.
      required:
        - filter_id
        - selected_values
    RangeFilterSelectedRangeLower:
      oneOf:
        - type: integer
        - type: string
        - type: number
          format: double
    RangeFilterSelectedRangeUpper:
      oneOf:
        - type: integer
        - type: string
        - type: number
          format: double
    RangeFilterSelectedRange:
      type: object
      properties:
        lower:
          $ref: '#/components/schemas/RangeFilterSelectedRangeLower'
          description: Your selected lower bound for the range.
        upper:
          $ref: '#/components/schemas/RangeFilterSelectedRangeUpper'
          description: Your selected upper bound for the range.
    RangeFilterWeightingsSelectedRangeLower:
      oneOf:
        - type: integer
        - type: string
        - type: number
          format: double
    RangeFilterWeightingsSelectedRangeUpper:
      oneOf:
        - type: integer
        - type: string
        - type: number
          format: double
    RangeFilterWeightingsSelectedRange:
      type: object
      properties:
        lower:
          $ref: '#/components/schemas/RangeFilterWeightingsSelectedRangeLower'
        upper:
          $ref: '#/components/schemas/RangeFilterWeightingsSelectedRangeUpper'
    RangeFilterWeightings:
      type: object
      properties:
        selected_range:
          $ref: '#/components/schemas/RangeFilterWeightingsSelectedRange'
        weighting:
          type: number
          format: double
      required:
        - selected_range
        - weighting
    RangeFilter:
      type: object
      properties:
        filter_id:
          type: string
          description: ID of the "range" type filter.
        selected_range:
          $ref: '#/components/schemas/RangeFilterSelectedRange'
          description: >-
            This schema applies for filters of the `range` type, as defined in
            the [filter list
            response](\#tag/Filters/paths/~1api~1v1~1filters~1/get).


            A dictionary with two possible objects, 'lower' and 'upper'. At
            least one must be present and a non-null value.


            The expected data type for these values is defined by the `range`
            filter's `data_type` (see response linked above).


            If the data_type is a date, string format should be a parseable
            ISO8601 date string. Date values should be provided as a string in
            ISO 8601 format.


            Leaving a value as null will result in that bound being set to the
            lowest or highest possible value, depending on whether it is the
            upper or lower bound.
        weightings:
          $ref: '#/components/schemas/RangeFilterWeightings'
          description: >-
            Ratios to control the distribution of participants across the
            selected values.


            Integers and exact quantities are valid inputs.
      required:
        - filter_id
        - selected_range
    RequirementsCountRequestFiltersItems:
      oneOf:
        - $ref: '#/components/schemas/SelectFilter'
        - $ref: '#/components/schemas/RangeFilter'
    RequirementsCountRequest:
      type: object
      properties:
        filters:
          type: array
          items:
            $ref: '#/components/schemas/RequirementsCountRequestFiltersItems'
          description: >-
            List of filters to apply to the count. This parameter uses the new,
            simplified

            filters schema for interacting with eligibility.
        workspace_id:
          type: string
          description: >-
            The ID of the workspace you will be creating a study in.


            Due to US tax laws, non US residents may not participate in studies
            created by US researchers.

            For this reason, we use the country specified in the workspace to
            determine eligibility.


            If you do not specify a workspace ID, we will use the current
            workspace ID of the user making the request.

            Your eligibility count may not be accurate if you do not specify a
            workspace ID.
        organisation_id:
          type: string
          description: The ID of the workspace you will be creating a filterset in.
      required:
        - filters
    RequirementsCount:
      type: object
      properties:
        count:
          type: number
          format: double
          description: Number of participants passing all the requirements
      required:
        - count

```

## SDK Code Examples

```python
import requests

url = "https://api.prolific.com/api/v1/eligibility-count/"

payload = {
    "filters": [
        {
            "field": "age",
            "operator": "gte",
            "value": 18
        },
        {
            "field": "enrollment_status",
            "operator": "eq",
            "value": "active"
        },
        {
            "field": "gender",
            "operator": "in",
            "value": ["female", "non-binary"]
        }
    ],
    "workspace_id": "645e4403bdd06d5f66d8fbd8"
}
headers = {
    "Authorization": "<apiKey>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.prolific.com/api/v1/eligibility-count/';
const options = {
  method: 'POST',
  headers: {Authorization: '<apiKey>', 'Content-Type': 'application/json'},
  body: '{"filters":[{"field":"age","operator":"gte","value":18},{"field":"enrollment_status","operator":"eq","value":"active"},{"field":"gender","operator":"in","value":["female","non-binary"]}],"workspace_id":"645e4403bdd06d5f66d8fbd8"}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

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

func main() {

	url := "https://api.prolific.com/api/v1/eligibility-count/"

	payload := strings.NewReader("{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "<apiKey>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.prolific.com/api/v1/eligibility-count/")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<apiKey>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}"

response = http.request(request)
puts response.read_body
```

```java
HttpResponse<String> response = Unirest.post("https://api.prolific.com/api/v1/eligibility-count/")
  .header("Authorization", "<apiKey>")
  .header("Content-Type", "application/json")
  .body("{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}")
  .asString();
```

```php
<?php

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.prolific.com/api/v1/eligibility-count/', [
  'body' => '{
  "filters": [
    {
      "field": "age",
      "operator": "gte",
      "value": 18
    },
    {
      "field": "enrollment_status",
      "operator": "eq",
      "value": "active"
    },
    {
      "field": "gender",
      "operator": "in",
      "value": [
        "female",
        "non-binary"
      ]
    }
  ],
  "workspace_id": "645e4403bdd06d5f66d8fbd8"
}',
  'headers' => [
    'Authorization' => '<apiKey>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
var client = new RestClient("https://api.prolific.com/api/v1/eligibility-count/");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "<apiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "<apiKey>",
  "Content-Type": "application/json"
]
let parameters = [
  "filters": [
    [
      "field": "age",
      "operator": "gte",
      "value": 18
    ],
    [
      "field": "enrollment_status",
      "operator": "eq",
      "value": "active"
    ],
    [
      "field": "gender",
      "operator": "in",
      "value": ["female", "non-binary"]
    ]
  ],
  "workspace_id": "645e4403bdd06d5f66d8fbd8"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.prolific.com/api/v1/eligibility-count/")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```

```python
import requests

url = "https://api.prolific.com/api/v1/eligibility-count/"

payload = {
    "filters": [
        {
            "field": "age",
            "operator": "gte",
            "value": 18
        },
        {
            "field": "enrollment_status",
            "operator": "eq",
            "value": "active"
        },
        {
            "field": "gender",
            "operator": "in",
            "value": ["female", "non-binary"]
        }
    ],
    "workspace_id": "645e4403bdd06d5f66d8fbd8"
}
headers = {
    "Authorization": "<apiKey>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.prolific.com/api/v1/eligibility-count/';
const options = {
  method: 'POST',
  headers: {Authorization: '<apiKey>', 'Content-Type': 'application/json'},
  body: '{"filters":[{"field":"age","operator":"gte","value":18},{"field":"enrollment_status","operator":"eq","value":"active"},{"field":"gender","operator":"in","value":["female","non-binary"]}],"workspace_id":"645e4403bdd06d5f66d8fbd8"}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

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

func main() {

	url := "https://api.prolific.com/api/v1/eligibility-count/"

	payload := strings.NewReader("{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "<apiKey>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.prolific.com/api/v1/eligibility-count/")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<apiKey>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}"

response = http.request(request)
puts response.read_body
```

```java
HttpResponse<String> response = Unirest.post("https://api.prolific.com/api/v1/eligibility-count/")
  .header("Authorization", "<apiKey>")
  .header("Content-Type", "application/json")
  .body("{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}")
  .asString();
```

```php
<?php

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.prolific.com/api/v1/eligibility-count/', [
  'body' => '{
  "filters": [
    {
      "field": "age",
      "operator": "gte",
      "value": 18
    },
    {
      "field": "enrollment_status",
      "operator": "eq",
      "value": "active"
    },
    {
      "field": "gender",
      "operator": "in",
      "value": [
        "female",
        "non-binary"
      ]
    }
  ],
  "workspace_id": "645e4403bdd06d5f66d8fbd8"
}',
  'headers' => [
    'Authorization' => '<apiKey>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
var client = new RestClient("https://api.prolific.com/api/v1/eligibility-count/");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "<apiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"filters\": [\n    {\n      \"field\": \"age\",\n      \"operator\": \"gte\",\n      \"value\": 18\n    },\n    {\n      \"field\": \"enrollment_status\",\n      \"operator\": \"eq\",\n      \"value\": \"active\"\n    },\n    {\n      \"field\": \"gender\",\n      \"operator\": \"in\",\n      \"value\": [\n        \"female\",\n        \"non-binary\"\n      ]\n    }\n  ],\n  \"workspace_id\": \"645e4403bdd06d5f66d8fbd8\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "<apiKey>",
  "Content-Type": "application/json"
]
let parameters = [
  "filters": [
    [
      "field": "age",
      "operator": "gte",
      "value": 18
    ],
    [
      "field": "enrollment_status",
      "operator": "eq",
      "value": "active"
    ],
    [
      "field": "gender",
      "operator": "in",
      "value": ["female", "non-binary"]
    ]
  ],
  "workspace_id": "645e4403bdd06d5f66d8fbd8"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.prolific.com/api/v1/eligibility-count/")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```