> For the complete documentation index, see [llms.txt](https://docs.kairos.com/documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.kairos.com/documentation/full-api-reference/liveness-verification.md).

# Liveness Verification

## Introduction

This API allows you to perform liveness verification using a selfie image. It analyzes the provided image and returns information about the detected face, including its liveness score.

### Authentication

To access the API, you need to include the following headers in your request:

* `app_id`: Your application's unique identifier.
* `app_key`: Your application's authentication key.

#### Postman Collection

Open the [Kairos Postman Collection](https://www.postman.com/martian-shuttle-95013/kairos-public/collection/0cj8cw1/kairos-idv-apis) to explore and test our APIs.

#### Submit Verification Request

Submit a verification request by providing a selfie image.

* **URL**: `https://idv-eu.kairos.com/v0.2/liveness-verification`
* **Method**: `POST`
* **Headers**:
  * `Content-Type`: `multipart/form-data`
  * `app-id`: Your API application ID.
  * `app-key`: Your API application key.
* **Body**:
  * `selfie` (File) - The selfie image file for liveness verification. 
  * `threshold` (Numeric Value) - A numeric value (between 0 and 1) representing the threshold for liveness verification. The API will consider a face as live if its liveness score is greater than or equal to this threshold.

**Image Size Requirements**:

* `selfie` — minimum 300 px, recommended > 900 px, maximum 5000 px.

**Sample Request**

To make a liveness verification request, you can use the following examples:

{% tabs %}
{% tab title="Node.js" %}

```
var request = require('request');
var fs = require('fs');
var options = {
  'method': 'POST',
  'url': 'https://idv-eu.kairos.com/v0.2/liveness-verification',
  'headers': {
    'app_id': 'put_app_id_here',
    'app_key': 'put_app_key_here'
  },
  formData: {
    'selfie': {
      'value': fs.createReadStream('/path/to/selfie_image'),
      'options': {
        'filename': 'selfie.jpg'
      }
    },
    'threshold': '0.6'
  }
};
request(options, function (error, response) {
  if (error) throw new Error(error);
  console.log(response.body);
});
```

{% endtab %}

{% tab title="Python" %}

```python
import requests

url = "https://idv-eu.kairos.com/v0.2/liveness-verification"
files=[
    ('selfie',('file',open('/path/to/selfie_image','rb')))
]
headers = {
    'app_id': 'put_app_id_here',
    'app_key': 'put_app_key_here'
}

# Add threshold parameter
payload = {
    'threshold': 0.6
}

response = requests.request("POST", url, headers=headers, files=files, data=payload)

```

{% endtab %}

{% tab title="cURL" %}

```sh
curl -X POST --location 'https://idv-eu.kairos.com/v0.2/liveness-verification' \
--header 'app_id: put_app_id_here' \
--header 'app_key: put_app_key_here' \
--form 'selfie=@"/path/to/selfie_image"' \
--form 'threshold=0.6'
```

{% endtab %}
{% endtabs %}

Replace app\_id, app\_key, and selfie with your actual credentials and the path to your selfie image.

#### Response

* **Status Code:** 200 (OK)
* **Response Headers:**
  * `Content-Type` — Media type of the response. Always `application/json`.
  * `Content-Length` — Size of the response body in bytes.
  * `X-Request-ID` — A unique identifier assigned to each request. 
  * `X-Content-Type-Options: nosniff` — Prevents MIME type sniffing on the response.
  * `X-Frame-Options: DENY` — Prevents the response from being embedded in a frame or iframe.
  * `Strict-Transport-Security: max-age=86400; includeSubDomains` — Enforces HTTPS-only connections.
* **Response Body:**

```json
{
  "api_req_uid": "c6bb825f-871c-4323-8c06-8e5fd3517747",
  "processed_at": "2024-04-01 20:05:17",
  "requested_at": "2024-04-01 20:05:17",
  "response_code": 2,
  "response_data": {
    "faces_liveness": 0.0,
    "faces_predicted": [
      {
        "confidence": 0.9885,
        "delta": {
          "x": 18.9982,
          "y": 25.3957
        },
        "top_left": {
          "x": 38.0577,
          "y": 4.0824
        }
      }
    ],
    "img": {
      "height": 71,
      "width": 95
    }
  }
}
```

### Other Responses

* **5xx**: Server errors may occur, and the server will respond with an appropriate 5xx status code. In this case, please check your request and try again later.
* **4xx**: Authentication failures may result in a 4xx status code. Make sure you have provided valid `app_id` and `app_key` in the request headers.
* **403**: If limits are exceeded, you may receive a 403 Forbidden status code indicating that you have reached a usage limit. Check your account limits and consider upgrading your plan if needed.


---

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