LINE sign-in with Embedded Wallets

LINE Login lets users authenticate with a LINE account. Choose the default connection for the quickest setup, or configure a custom connection when you need your own LINE channel, consent screen, or identity provider.

Default LINE sign-in

The default connection uses the LINE OAuth credentials managed by Embedded Wallets. You don't need a LINE Developers Console channel.

Caveats

• The LINE consent screen identifies the OAuth application managed by Embedded Wallets, not your dapp.
• You can't change the LINE application configuration, such as its scopes or branding, because you don't own the credentials.
• The default connection and a custom connection are separate connections, so they produce different wallet addresses for the same person unless you link them with a group connection.

Configure the default connection

1. Open your project in the MetaMask Developer Dashboard.
2. Select Social Connections.
3. Enable LINE.

The SDK reads the connection from the dashboard. You don't need to add LINE credentials to your SDK configuration.

Custom LINE sign-in

Use a custom connection when the LINE authorization belongs to your dapp or an identity platform you control. Your LINE credentials sit in Auth0 or your own backend.

LINE credentials can't go in the dashboard

Google, Discord, and Twitch connections take only a client ID, because they accept https://auth.web3auth.io/auth as a redirect URI for a public client. LINE Login requires a channel secret to complete the token exchange, so Embedded Wallets doesn't accept a LINE channel ID on the social connection.

Preserve wallet addresses

Decide between the default and a custom connection before you onboard users. Moving from the default LINE connection to Auth0 or your own JWT connection changes every user's wallet address unless both connections are in a group connection with matching user identifiers.

Auth0

1. Configure LINE as a social connection in Auth0.
2. Create an Auth0 connection in the MetaMask Developer Dashboard.
3. For an implicit flow, call Embedded Wallets with the Auth0 connection ID and set the Auth0 connection name to line.
4. For a JWT flow, authenticate with the Auth0 SDK, retrieve its raw ID token, and pass that token to Embedded Wallets.

Firebase Authentication and Amazon Cognito don't offer LINE as a first-party social provider.

Your own backend

1. Complete LINE Login in your client and send the result to your backend.
2. Exchange the authorization code with LINE's token endpoint using your channel secret, then validate the ID token before trusting the identity.
3. Issue a fresh JWT with an iat no more than 60 seconds old and expose the signing public key through a JSON Web Key Set (JWKS) endpoint.
4. Create a custom JWT connection that validates your issuer, audience, JWKS, and user identifier.
5. Pass your JWT and custom connection ID to Embedded Wallets.

Don't send a LINE channel secret to a client application.

Group LINE connections

A group connection gives the same person one wallet address across several login methods.

Default LINE and LINE through Auth0 are separate connections. They produce different wallet addresses unless you group them and every connection in the group uses the same JWT user identifier (email or an aligned sub).

Pass both the child connection ID and grouped connection ID when you bypass the modal:

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<LINE_AUTH_CONNECTION_ID>',
  groupedAuthConnectionId: '<GROUPED_AUTH_CONNECTION_ID>',
  idToken,
})

Usage examples

The implicit examples open a LINE or Auth0 authorization flow. The JWT examples assume your Auth0 or backend integration has already returned a fresh ID token.

Default implicit flow

React

import { AUTH_CONNECTION, WALLET_CONNECTORS } from '@web3auth/modal'
import { useWeb3AuthConnect } from '@web3auth/modal/react'

const { connectTo } = useWeb3AuthConnect()

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.LINE,
})

Vue

import { AUTH_CONNECTION, WALLET_CONNECTORS } from '@web3auth/modal'
import { useWeb3AuthConnect } from '@web3auth/modal/vue'

const { connectTo } = useWeb3AuthConnect()

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.LINE,
})

JavaScript

import { AUTH_CONNECTION, WALLET_CONNECTORS } from '@web3auth/modal'

await web3auth.connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.LINE,
})

React Native

import { AUTH_CONNECTION, useWeb3AuthConnect } from '@web3auth/react-native-sdk'

const { connectTo } = useWeb3AuthConnect()

await connectTo({
  authConnection: AUTH_CONNECTION.LINE,
})

Android

val response = web3Auth.connectTo(
  LoginParams(AuthConnection.LINE)
)

iOS

let response = try await web3Auth.connectTo(
    loginParams: LoginParams(authConnection: .LINE)
)

Flutter

final response = await Web3AuthFlutter.login(
  LoginParams(loginProvider: Provider.line),
);

Unity

var options = new LoginParams
{
    loginProvider = Provider.LINE
};

web3Auth.login(options);

Unreal Engine

FWeb3AuthLoginParams LoginParams;
LoginParams.LoginProvider = TEXT("line");

UWeb3AuthSDK::GetInstance()->Login(LoginParams);

Auth0 implicit flow

These examples use the Auth0 custom connection configured for your SDK. Replace the connection ID and domain with your Auth0 values. For Android and iOS, add the connection to authConnectionConfig during initialization. Flutter, Unity, and Unreal Engine currently use their platform's loginConfig; configure it by following the custom authentication guide for Flutter, Unity, or Unreal Engine.

React

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<AUTH0_CONNECTION_ID>',
  extraLoginOptions: {
    connection: 'line',
  },
})

Vue

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<AUTH0_CONNECTION_ID>',
  extraLoginOptions: {
    connection: 'line',
  },
})

JavaScript

await web3auth.connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<AUTH0_CONNECTION_ID>',
  extraLoginOptions: {
    connection: 'line',
  },
})

React Native

await connectTo({
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<AUTH0_CONNECTION_ID>',
  extraLoginOptions: {
    connection: 'line',
  },
})

Android

val response = web3Auth.connectTo(
  LoginParams(
    authConnection = AuthConnection.CUSTOM,
    authConnectionId = "<AUTH0_CONNECTION_ID>",
    extraLoginOptions = ExtraLoginOptions(
      domain = "https://<AUTH0_DOMAIN>",
      connection = "line"
    )
  )
)

iOS

let response = try await web3Auth.connectTo(
    loginParams: LoginParams(
        authConnection: .CUSTOM,
        authConnectionId: "<AUTH0_CONNECTION_ID>",
        extraLoginOptions: ExtraLoginOptions(
            domain: "https://<AUTH0_DOMAIN>",
            connection: "line"
        )
    )
)

Flutter

final response = await Web3AuthFlutter.login(
  LoginParams(
    loginProvider: Provider.jwt,
    extraLoginOptions: ExtraLoginOptions(
      domain: 'https://<AUTH0_DOMAIN>',
      verifierIdField: 'sub',
      connection: 'line',
    ),
  ),
);

Unity

var options = new LoginParams
{
    loginProvider = Provider.JWT,
    extraLoginOptions = new ExtraLoginOptions
    {
        domain = "https://<AUTH0_DOMAIN>",
        verifierIdField = "sub",
        connection = "line"
    }
};

web3Auth.login(options);

Unreal Engine

The current Unreal Engine SDK documentation provides this flow through Blueprint configuration, not a verified C++ example. Configure the Auth0 connection by following the Unreal Engine custom authentication guide.

JWT flow

Obtain a fresh ID token from your identity aggregator or backend before calling Embedded Wallets. The token issuer and claims must match the custom connection in the dashboard.

React

const idToken = await getIdToken()

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<CUSTOM_CONNECTION_ID>',
  idToken,
})

Vue

const idToken = await getIdToken()

await connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<CUSTOM_CONNECTION_ID>',
  idToken,
})

JavaScript

const idToken = await getIdToken()

await web3auth.connectTo(WALLET_CONNECTORS.AUTH, {
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<CUSTOM_CONNECTION_ID>',
  idToken,
})

React Native

const idToken = await getIdToken()

await connectTo({
  authConnection: AUTH_CONNECTION.CUSTOM,
  authConnectionId: '<CUSTOM_CONNECTION_ID>',
  idToken,
})

Android

val response = web3Auth.connectTo(
  LoginParams(
    authConnection = AuthConnection.CUSTOM,
    authConnectionId = "<CUSTOM_CONNECTION_ID>",
    idToken = idToken
  )
)

iOS

let response = try await web3Auth.connectTo(
    loginParams: LoginParams(
        authConnection: .CUSTOM,
        authConnectionId: "<CUSTOM_CONNECTION_ID>",
        idToken: idToken
    )
)

Flutter

final response = await Web3AuthFlutter.login(
  LoginParams(
    loginProvider: Provider.jwt,
    extraLoginOptions: ExtraLoginOptions(
      id_token: idToken,
    ),
  ),
);

Unity

var options = new LoginParams
{
    loginProvider = Provider.JWT,
    extraLoginOptions = new ExtraLoginOptions
    {
        id_token = idToken
    }
};

web3Auth.login(options);

Unreal Engine

The current Unreal Engine SDK documentation doesn't provide a verified C++ JWT example. Configure the JWT connection and login in Blueprint by following the Unreal Engine custom authentication guide.

Node.js

const result = await web3auth.connect({
  authConnectionId: '<CUSTOM_CONNECTION_ID>',
  idToken,
})