> For the complete documentation index, see [llms.txt](https://docs.caf.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.caf.io/caf-sdk/ios/getting-started-with-the-sdk-1.md).

# Face Liveness

{% hint style="warning" %}

## This guide covers version 7.0.0 and above. For versions below 7.0.0, please see the [legacy documentation](/caf-sdk/ios/getting-started-with-the-sdk-5.md).

{% endhint %}

### Overview 

This guide covers the SDK installation, session initialization, and how to trigger the Face Liveness flow.

### Prerequisites 

Before proceeding, ensure the CAF SDK is properly installed. If you haven't done this yet, please refer to our [Installation Guide](https://www.google.com/search?q=%23).

### Starting the Face Liveness

To initiate the liveness flow, use the singleton instance and provide the required configuration parameters. Use the completion handler to manage the session events and results.

```swift
CerttaLiveness.shared.open(
    from: self, // This is the view controller and the delegate
    configuration: LivenessConfiguration(
        maxRetryAttempts: 3,
        faceAuthEnabled: false,
        showLoading: true,
        useFaceLivenessUi: true 
    )
) 
```

***

#### `LivenessConfiguration` Parameters

All parameters have defaults; override only what you need.

<table><thead><tr><th>Parameter</th><th width="279">Default</th><th>Description</th></tr></thead><tbody><tr><td><code>maxRetryAttempts</code></td><td><code>3</code></td><td>Maximum retries after a failed capture attempt.</td></tr><tr><td><code>faceAuthEnabled</code></td><td><code>false</code></td><td>When <strong>enabled</strong>, the SDK performs <strong>face authentication.</strong></td></tr><tr><td><code>showLoading</code></td><td><code>true</code></td><td>Shows loading indicators during processing when <strong>true</strong>.</td></tr><tr><td><code>useFaceLivenessUi</code></td><td><code>false</code></td><td>If <strong>enabled</strong>, the SDK uses the built-in Certta UI.</td></tr></tbody></table>

### Understanding Liveness Events & Results

The `CerttaLiveness.instance.open()` assignes your controller to a delegate that you need to declare those methods:&#x20;

{% hint style="warning" %}
Ensure the JWT response is evaluated on the backend. This process must include validating the token's signature and verifying the `isAlive` and `isMatch` fields. Do not perform these validations on the client side.
{% endhint %}

```swift
extension CerttaViewController: CerttaLivenessDelegate, CerttaDelegate {
    func didFinish(signedResponse: String) {
        let out = formView.outputView
        out.text += "✅ Capture completed successfully\n"    
    }

    func didFail(_ failure: LivenessFailure) {
    let out = formView.outputView
    switch failure {
    case .faceRecognitionFailure(let result, let cause):
        out.text += "❌ Liveness failed (face): cause=\(cause), result=\(result)\n\n"
    case .imageCaptureFailure(let message):
        out.text += "❌ Liveness failed (capture): \(message)\n\n"
        }
    }
  
    func didFinishWith(_ error: CerttaError) {
        let out = formView.outputView
        switch error {
        case .initializationError(let message): out.text += "❌ Error: \(message)\n\n"
        case .permissionError(let message): out.text += "❌ Error: permission - \(message)\n\n"
        case .securityError(let message): out.text += "❌ Error: security - \(message)\n\n"
        case .unknownError(let message): out.text += "❌ Error: \(message)\n\n"
        case .networkError(let message): out.text += "❌ Error: network - \(message)\n\n"
        }
    }
    func didLog(level: String, message: String) {
        print("level: \(level), message: \(message)")
    }
}
```

#### &#x20;`didFinish(signedResponse: String)`

The  string is the **signed result** from the module. Your backend or CAF integration documentation defines how to **validate**, **decode**, and **store** it. Do **not** log the full token in production builds.

#### `didFail(_ failure: LivenessFailure)`

There are two types of **`LivenessFailure`**:

| Case                                                       | When                                                                                                                                                          |
| ---------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `.imageCaptureFailure(String)`                             | Problems during **capture** (environment, timeout, no face, provider-specific messages, etc.). The string is intended for **diagnostics** or UX messaging.    |
| `.faceRecognitionFailure(response: String, cause: String)` | Capture succeeded but **face recognition / backend** did not accept the result. **`cause`** explains the rejection and **`result`** is the **signed payload** |

#### `didFinishWith(_ error: CerttaError)`

Triggered when a technical blocker prevents the SDK from starting or finishing the process, such as denied camera permissions, no internet connection, or hardware initialization failures.

| Event                     | Typical cause                                                                          |
| ------------------------- | -------------------------------------------------------------------------------------- |
| **`initializationError`** | **`configure`** not called, empty token or user ID, or invalid **`maxRetryAttempts`**. |
| **`permissionError`**     | Camera (or related) permission denied.                                                 |
| **`networkError`**        | Connectivity or server-side issues surfaced as network class errors.                   |
| **`securityError`**       | Security checks failed.                                                                |
| **`unknownError`**        | Other failures not mapped to a specific case.                                          |

**`CerttaError`** conforms to **`LocalizedError`**. Use **`localizedDescription`** (or **`message`**) in alerts.

#### `didLog(level: String, message: String)`

Used for **progress** and **informational** events, for example:

* Loading / Loaded states: messages you can map to UI or analytics.

***

### Permissions and user experience

* Request camera access **before** opening Face Liveness if your app flow allows it; otherwise the SDK may return **`permissionError`**.
* Ensure good lighting and copy that explains **why** the user must complete a short live capture.

***

## Colors Theming

* **Certta**: use the session **`colorConfiguration`** and **`useFaceLivenessUi`** in **`LivenessConfiguration`** to customize the Face Liveness UI.
* **Dark / light mode**: build **`CafColorConfiguration`** using **`UITraitCollection.current.userInterfaceStyle`** if you need different palettes

```swift
Certta.shared.setColorConfiguration(CafColorConfiguration(
        primaryColor: "#FFFFFF",
        secondaryColor: "#222222",
        contentColor: "#FFFFFF",
        backgroundColor: "#000000",
        mediumColor: "#555555",
        dialogBackgroundColor: "#1C1C1E",
        dialogBorderColor: "#E5E5E7"
      )
)
```

| Property                | Type     | Description                             | Format                     |
| ----------------------- | -------- | --------------------------------------- | -------------------------- |
| `primaryColor`          | `String` | Primary buttons, highlights.            | Hex code (e.g., `#FF0000`) |
| `secondaryColor`        | `String` | Secondary elements, borders.            | Hex code                   |
| `contentColor`          | `String` | Text and icons.                         | Hex code                   |
| `backgroundColor`       | `String` | Screen background.                      | Hex code                   |
| `mediumColor`           | `String` | Neutral elements (e.g., progress bars). | Hex code                   |
| `dialogBackgroundColor` | `String` | Dialog and popup background color.      | Hex code                   |
| `dialogBorderColor`     | `String` | Dialog and popup border color.          | Hex code                   |

***

### Release notes

See [**Changelog**](/caf-sdk/ios/getting-started-with-the-sdk-4.md) for versions, breaking changes, and minimum Xcode / iOS.

***

## Technical Support and Usage Tips

For more details and advanced usage scenarios, refer to the following resources:

* **GitHub Repository:** access the source code, issue tracking, and release notes in the [CafSDK GitHub repository](https://github.com/combateafraude/caf-ios-sdk).
* **FAQs and Troubleshooting**: check our FAQ section for common issues and troubleshooting tips.
* **Support**: for additional assistance, contact our support team or join our developer community forum.

We continuously update the documentation as new features and improvements are released. Stay up to date for future updates!


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