> For the complete documentation index, see [llms.txt](/llms.txt).

# Advanced configuration

The Web3Auth by MetaMask, Embedded Wallet SDK provides extensive configuration options that allow you to customize authentication flows, UI appearance, blockchain integrations, and security features to meet your application's specific requirements.

## Configuration structure

When setting up Embedded Wallets, you'll pass in the options to the constructor. This consists of:

```dart
import 'package:web3auth_flutter/web3auth_flutter.dart';
import 'package:web3auth_flutter/enums.dart';
import 'package:web3auth_flutter/input.dart';
import 'package:web3auth_flutter/output.dart';
import 'dart:io';

Future<void> initWeb3Auth() async {

  late final String redirectUrl;

  if (Platform.isAndroid) {
    redirectUrl = 'w3a://com.example.w3aflutter';
  } else {
    redirectUrl = 'com.example.w3aflutter://auth';
  }


  await Web3AuthFlutter.init(Web3AuthOptions(
    clientId: "YOUR_WEB3AUTH_CLIENT_ID", // Pass your Web3Auth Client ID, ideally using an environment variable // Get your Client ID from MetaMask Developer Dashboard dashboard
    web3AuthNetwork: Web3AuthNetwork.sapphire_mainnet, // or Web3AuthNetwork.sapphire_devnet
    redirectUrl: redirectUrl,
  ));

}

```

### `Web3AuthOptions`

The Web3Auth Constructor takes an object with `Web3AuthOptions` as input.

**Table**

| Parameter               | Description                                                                                                                    |
| ----------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| `clientId`              | Your Web3Auth Client ID from the [Dashboard](https://developer.metamask.io/). Mandatory `String`.                              |
| `web3AuthNetwork`       | Web3Auth Network: `sapphire_mainnet`, `sapphire_devnet`, `mainnet`, `cyan`, `aqua`, or `testnet`. Mandatory `Web3AuthNetwork`. |
| `redirectUrl`           | URL that Web3Auth redirects to after successful authentication. Mandatory `String`.                                            |
| `whiteLabel?`           | Whitelabel options for custom UI, branding, and translations. Takes `WhiteLabelData` as a value.                               |
| `authConnectionConfig?` | Auth connection config for custom connections. Takes `List<AuthConnectionConfig>` as a value.                                  |
| `chains?`               | Chain configuration for Wallet Services and signing. Takes `List<Chains>` as a value.                                          |
| `defaultChainId?`       | Default chain ID from the `chains` list.                                                                                       |
| `mfaSettings?`          | Configure MFA settings for authentication. Takes `MfaSettings` as a value.                                                     |
| `sessionTime?`          | Configure session management time in seconds. Default is 30 days. Max 30 days.                                                 |

**Class**

```dart
class Web3AuthOptions {
  final String clientId;
  final Web3AuthNetwork web3AuthNetwork;
  final BuildEnv? authBuildEnv;
  final String redirectUrl;
  final WhiteLabelData? whiteLabel;
  final List<AuthConnectionConfig>? authConnectionConfig;
  final List<Chains>? chains;
  final String? defaultChainId;
  final bool? useSFAKey;
  final MfaSettings? mfaSettings;
  final int sessionTime;

  Web3AuthOptions({
    required this.clientId,
    required this.web3AuthNetwork,
    this.authBuildEnv = BuildEnv.production,
    required this.redirectUrl,
    this.whiteLabel,
    this.authConnectionConfig = const [],
    this.chains,
    this.defaultChainId,
    this.useSFAKey = false,
    this.sessionTime = 30 * 86400,
    this.mfaSettings,
  });
}

```

## Session management

Control how long users stay authenticated and how sessions persist. The session key is stored in the device's encrypted Keystore.

**Key Configuration Options:**

- `sessionTime` - Session duration in seconds. Controls how long users remain authenticated before needing to log in again.  
  - Minimum: 1 second (`1`).
  - Maximum: 30 days (`86400 * 30`).
  - Default: 30 days (`30 * 86400`).

```dart
await Web3AuthFlutter.init(Web3AuthOptions(
    clientId: "YOUR_WEB3AUTH_CLIENT_ID", // Pass your Web3Auth Client ID, ideally using an environment variable // Get your Client ID from MetaMask Developer Dashboard dashboard
    web3AuthNetwork: Web3AuthNetwork.sapphire_mainnet, // or Web3AuthNetwork.sapphire_devnet
    sessionTime: 30 * 86400, // 30 days (in seconds)
    redirectUrl: redirectUrl,
));

```

## Custom authentication methods

Control the login options presented to your users. For detailed configuration options and implementation examples, see the [custom authentication](/embedded-wallets/sdk/flutter/advanced/custom-authentication/) section.

## UI customization

Customize the brand experience by customizing the Web3Auth Login Screens to match your application's design. For complete customization options, refer to the [whitelabeling and UI customization](/embedded-wallets/sdk/flutter/advanced/whitelabel/) section.

## Multi-Factor Authentication (MFA)

Add additional security layers to protect user accounts with two-factor authentication. See the [detailed configuration options and implementation examples](/embedded-wallets/sdk/flutter/advanced/mfa/).

**Key Configuration Options:**

- `mfaSettings` - Configure MFA settings for different authentication flows
- `mfaLevel` - Control when users are prompted to set up MFA