LIFF v2 API reference

# LIFF v2 API reference

# Common specifications

# Operating environment

For more information about supported operating environments for LIFF v2, see Overview in the LIFF documentation.

Which functions you can use depends on whether the LIFF app is opened in a LIFF browser or an external browser. For example, you can't use liff.scanCode() in an external browser. For more information, see the descriptions for each client API.

LIFF apps are not compatible with OpenChat

For example, retrieving a user's profile information through a LIFF app isn't possible in most cases.

# LIFF SDK errors

LIFF SDK errors are returned in LiffError objects.

Example

# LiffError object

code

String

Error code

message

String

Not always included

Error message

cause

Unknown

Not always included

Error cause

# Error details

Error code Description
400 Problem with the request. Check the request parameters and JSON format.
401 Check that the authorization header is correct.
403 Not authorized to use the API. Confirm that your account or plan is authorized to use the API.
429 Make sure that you are within the rate limit for requests.
500 Temporary error on the API server.
INIT_FAILED Failed to init LIFF SDK.
INVALID_ARGUMENT An invalid argument was specified.
UNAUTHORIZED
  • The user did not authorize.
  • Call the server api without access token.
  • Call the share target picker before logging in.
FORBIDDEN
  • You don't have the required permission.
  • You attempted to use a feature in an environment that's not supported.
INVALID_CONFIG An invalid setting.
INVALID_ID_TOKEN Failed to verify the ID token.
EXCEPTION_IN_SUBWINDOW Problem with subwindow.
  • For example, if the target picker (group or friend selection screen) is displayed and has been idle for more than 10 minutes, for example.
THINGS_NO_LINKED_DEVICES No linked device is available.
BLUETOOTH_SETTING_OFF Bluetooth is off.
THINGS_TERMS_NOT_AGREED LINE Things TOS is not agreed.
BLUETOOTH_NO_LOCATION_PERMISSION Location permission is not granted.
BLUETOOTH_LOCATION_DISABLED Location setting is off.
BLUETOOTH_LE_API_UNAVAILABLE The BLE API for LIFF is not available on this device.
BLUETOOTH_CONNECT_FAILED Failed to connect to the device.
BLUETOOTH_ALREADY_CONNECTED The device is already connected.
BLUETOOTH_CONNECTION_LOST No device is connected.
BLUETOOTH_UNSUPPORTED_OPERATION The specified operation is not supported for the specified characteristic.
BLUETOOTH_SERVICE_NOT_FOUND The specified service does not exist in the GATT server.
BLUETOOTH_CHARACTERISTIC_NOT_FOUND The specified characteristic does not exist in the service.
UNKNOWN Unknown error.

# LIFF SDK properties

# liff.id

The property that holds the LIFF app ID (String type) passed to liff.init().

The value of liff.id is null until you run liff.init().

Example

# liff.ready

A property holding the Promise object that resolves when you run liff.init() for the first time after starting the LIFF app.

If you use liff.ready, you can execute any process after the completion of liff.init().

This property can be used before the LIFF app is initialized

You can use liff.ready even before the initialization of the LIFF app by liff.init() has finished.

Example

Note

If liff.init() fails, liff.ready will not be rejected. Also, it doesn't return a LiffError object.

# Initialization

# liff.init()

Initializes a LIFF app. You can only call other LIFF SDK methods after calling liff.init(). The LIFF SDK obtains the access token and ID token of the user from the LINE Platform when you initialize the LIFF app.

Note on initializing the LIFF app

  • The liff.init() method performs initialization processing based on information such as liff.state and access_token=xxx given to the primary redirect URL. If your endpoint URL includes a query parameter or path, to properly initialize the LIFF app, execute the liff.init() method once for both the primary redirect URL and the secondary redirect URL. For more information, see Behaviors from accessing the LIFF URL to opening the LIFF app.

  • Don't change the URL during server or front-end processing before the Promise object returned by the liff.init() method is resolved. If you change the URL, it will return 'INIT_FAILED' and the LIFF app can't be opened. For example, if you perform redirects using location.replace() after running liff.init(), design it so that the screen transitions after the Promise object is resolved.

    liff.init({ liffId: myLiffId }).then(() => {
  // Redirect to another page after the returned Promise object has been resolved
  location.replace("https://line.me/{liffId}/path");
});

  • The access_token=xxx automatically granted to the primary redirect URL is the user's access token (confidential information). Don't send the primary redirect URL to an external logging tool such as Google Analytics.
    Note that in LIFF v2.11.0 or later, credential information is excluded from URLs when liff.init() is resolved. Therefore, you can prevent leaking credential information by sending the page view in the then() method as follows. If you want to use logging tools, we recommend that you upgrade your LIFF app to v2.11.0 or later. For more information about the updates in LIFF v2.11.0, see Release Notes in the LIFF documentation.

    liff.init({ liffId: myLiffId }).then(() => {
  ga("send", "pageview");
});
LIFF app's query parameters

When you access a LIFF URL or perform a transition between LIFF apps, the URL may be given query parameters that begin with liff.*.

e.g.

  • liff.state (indicates additional information specified in LIFF URL)
  • liff.referrer (indicates where the referrer came from when transitioning between LIFF apps. For more information, see Get URL from before LIFF-to-LIFF transition)

The above query parameters are given by the SDK so that LIFF apps can function properly. When you independently alter the above query parameters, proper opening of the LIFF app and a transition between LIFF apps may not be guaranteed. Implement your app so that the liff.* query parameter is altered after liff.init() is resolved.

Functions that can be executed even before the LIFF app is initialized

This property or methods are available even before the liff.init() method is executed.

You can get the environment in which the LIFF app is running before initializing the LIFF app, or close the LIFF app when the LIFF app initialization fails.

To use the liff.closeWindow() method before the initialization of the LIFF app by liff.init() has finished, your LIFF SDK version must be v2.4.0 or later.

Example

# Syntax

liff.init(config, successCallback, errorCallback);

# Arguments

config

Object

Required

LIFF app configurations

config.liffId

String

Required

LIFF app ID. Can be obtained when you add the LIFF app to your channel. For more information, see Adding a LIFF app to your channel.
The LIFF app ID specified here can be obtained with liff.id.

config.withLoginOnExternalBrowser

Boolean

Optional

Using either of the following values, specify whether or not to automatically execute the liff.login() method when initializing a LIFF app in an external browser. The default value is false.

  • true: Automatically execute the liff.login() method in external browsers
  • false: Don't automatically execute the liff.login() method in external browsers

successCallback

Function

Optional

Callback to return a data object upon successful initialization of the LIFF app.

Note

successCallback is processed at the same time that the Promise object of the return value is resolved. However, there is no set order to which is processed first.

errorCallback

Function

Optional

Callback to return an error object upon failure to initialize the LIFF app.

Note

errorCallback is processed at the same time that the Promise object of the return value is rejected. However, there is no set order to which is processed first.

# Return value

Returns a Promise object.

# Error response

When the Promise is rejected, LiffError is passed.

# Getting environment

# liff.getOS()

Gets the environment in which the user is running the LIFF app.

This method can be used before the LIFF app is initialized

You can use this method even before the initialization of the LIFF app by liff.init() has finished.

# Syntax

liff.getOS();

# Arguments

None

# Return value

The environment in which the user is running the LIFF app is returned as a string. Since the return value is based on the name of the OS in the user agent string, the return value is independent of the browser type (LIFF browser, LINE's in-app browser, external browser).

For example, if the user is using iOS, ios will be returned, regardless of whether the user is using LIFF browser or Safari.

Return value Description
ios iOS or iPadOS
android Android
web Other than the above

For more information about LIFF app supported operating systems and browsers, see Operating environment.

# liff.getLanguage()

Gets the language settings of the environment in which the LIFF app is running.

This method can be used before the LIFF app is initialized

You can use this method even before the initialization of the LIFF app by liff.init() has finished.

# Syntax

liff.getLanguage();

# Arguments

None

# Return value

String containing language settings specified in navigator.language in the LIFF app's running environment.

# liff.getVersion()

Gets the version of the LIFF SDK.

This method can be used before the LIFF app is initialized

You can use this method even before the initialization of the LIFF app by liff.init() has finished.

# Syntax

liff.getVersion();

# Arguments

None

# Return value

The version of the LIFF SDK is returned as a string.

# liff.getLineVersion()

Gets the user's LINE version.

This method can be used before the LIFF app is initialized

You can use this method even before the initialization of the LIFF app by liff.init() has finished.

# Syntax

liff.getLineVersion();

# Arguments

None

# Return value

If a user opens the LIFF app using a LIFF browser, the LINE version of the user is returned as a string. If a user opens the LIFF app using an external browser, null is returned.

# liff.getContext()

Gets the screen type (1-on-1 chat, group chat, multi-person chat, or external browser) from which the LIFF app is launched.

We've discontinued providing company internal identifiers of chat rooms to LIFF apps

We've discontinued providing company internal identifiers of chat rooms (one-on-one chat ID, group ID, and room ID) to LIFF apps. For more information, see the news from February 6, 2023, We've discontinued providing company internal identifiers of chat rooms to LIFF apps as of February 6, 2023.

Example

# Syntax

liff.getContext();

# Arguments

None

# Return value

A data object that contains the information necessary to make various API calls.

type

String

The type of screen from where the LIFF app was launched. One of:

  • utou: 1-on-1 chat
  • group: Group chat
  • room: Multi-person chat
  • external: External browser
  • none: A screen other than a 1-on-1 chat, group chat, multi-person chat, or external browser. For example, Wallet tab.

This property is also returned for LIFF apps after transitioning between LIFF apps.

viewType

String

Size of the LIFF app view, only returned if the type property is utou, room, or group. One of:

  • compact
  • tall
  • full

For more information, see Adding the LIFF app to a channel.

accessTokenHash

String

First half of the hashed SHA256 value of the access token. Used to validate the access token.

userId

String

User ID. Included when the type property is utou, room, group, none or external. However, null may be returned when type is external.

availability.shareTargetPicker.permission

Boolean

Specifies whether liff.shareTargetPicker() is available in the environment in which the LIFF app was launched.

  • true: liff.shareTargetPicker() is available.
  • false: liff.shareTargetPicker() isn't available.

*To get information about the availability of liff.shareTargetPicker(), we highly recommend using liff.isApiAvailable('shareTargetPicker') instead.

availability.shareTargetPicker.minVer

String

The minimum LINE version that supports liff.shareTargetPicker().

availability.multipleLiffTransition.permission

Boolean

Displays whether it's possible to transition to another LIFF app without closing the LIFF app within the LIFF browser.

  • true: It's possible to open another LIFF app without closing the currently opened LIFF app.
  • false: It's not possible to open another LIFF app without closing the currently opened LIFF app.

*To get information about the availability of a transition between multiple LIFF apps, we highly recommend using liff.isApiAvailable('multipleLiffTransition') instead.

availability.multipleLiffTransition.minVer

String

The minimum LINE version that supports opening another LIFF app without closing the currently opened LIFF app.

endpointUrl

String

URL of the service endpoint.

permanentLinkPattern

String

How additional information in LIFF URLs is handled. concat is returned.

For more information, see Opening a LIFF app in the LIFF documentation.

liffId

String

LIFF ID.

utouId

String

Discontinued

This property was discontinued. For more information, see the news from February 6, 2023, We've discontinued providing company internal identifiers of chat rooms to LIFF apps as of February 6, 2023.

groupId

String

Discontinued

This property was discontinued. For more information, see the news from February 6, 2023, We've discontinued providing company internal identifiers of chat rooms to LIFF apps as of February 6, 2023.

roomId

String

Discontinued

This property was discontinued. For more information, see the news from February 6, 2023, We've discontinued providing company internal identifiers of chat rooms to LIFF apps as of February 6, 2023.

Example (LIFF browser)

Example (external browser)

# liff.isInClient()

Determines whether the LIFF app is running in a LIFF browser.

This method can be used before the LIFF app is initialized

You can use this method even before the initialization of the LIFF app by liff.init() has finished.

# Syntax

liff.isInClient();

# Arguments

None

# Return value

# liff.isLoggedIn()

Checks whether the user is logged in.

Example

# Syntax

liff.isLoggedIn();

# Arguments

None

# Return value

  • true: The user is logged in
  • false: The user is not logged in

# liff.isApiAvailable()

Checks whether the specified API is available in the environment where you started the LIFF app. Specifically, it verifies whether the current LINE version supports the API and whether the terms and conditions for the API have been accepted.

Example

# Syntax

liff.isApiAvailable(apiName);

# Arguments

apiName

String

Required

The name of the LIFF client API. You can currently specify these API names:

About multipleLiffTransition

multipleLiffTransition is a property which indicates whether it's possible to open another LIFF app without closing the current LIFF app (LIFF-to-LIFF transition). It is not the name of an API. For more information, see Opening a LIFF app from another LIFF app (LIFF-to-LIFF transition) in the LIFF documentation.

# Return value

Returns whether the specified API is available in the current environment. If available, true is returned. If not, false is returned. Examples of false returned are as follows:

  • If the LIFF app was launched with a LINE version that doesn't support the API
  • If the LIFF app was launched in an external browser, even though the API isn't available in an external browser
  • If the terms and conditions haven't been accepted, even though you must accept them to use the API
  • If the user isn't logged in, even though the user must be logged in to use the API
  • If the access token is expired, even though the access token must be valid to use the API

# Authentication

# liff.login()

Performs the login process in the LINE's in-app browser or external browser.

Note

You can't use liff.login() in a LIFF browser, as it is automatically executed when liff.init() is executed.

Authorization requests within LIFF browser

The behavior of LINE Login authorization requests within the LIFF browser isn't guaranteed. Also, when opening LIFF apps from an external browser or LINE's in-app browser, make sure to use this method for the login process, not the authorization requests with LINE Login.

Example

# Syntax

liff.login(loginConfig);

# Arguments

loginConfig

Object

Optional

Login configurations

loginConfig.redirectUri

String

Optional

URL to open in the LIFF app after logging in. The default value is the URL set in Endpoint URL. For more information on how to set Endpoint URL, see Adding a LIFF app to your channel in the LIFF documentation.

If the URL specified in redirectUri doesn't start with the URL specified in Endpoint URL, the login process fails and an error screen is displayed.

For example, if Endpoint URL is https://example.com/path1/path2?query1=value1, the success or failure of the login process is as follows. Query parameters and URL fragments don't affect the success or failure of the login process.

redirectUri Login process
  • https://example.com/path1/path2?query1=value1
  • https://example.com/path1/path2?query2=value2
  • https://example.com/path1/path2#URL-fragment
  • https://example.com/path1/path2
  • https://example.com/path1/path2/
  • https://example.com/path1/path2/path3
 ✅ Success
  • https://example.com/path1
  • https://example.com/
  • https://example.com/path2/path1
 ❌ Failure

# Return value

None

# liff.logout()

Logs out.

Example

# Syntax

liff.logout();

# Arguments

None

# Return value

None

# liff.getAccessToken()

Gets the current user's access token.

You can use the access token obtained with this API to send user data from the LIFF app to the server. For more information, see Using user data in LIFF apps and servers in the LIFF documentation.

Expiration date of the access token

The access token is valid for 12 hours after being issued. When the user closes the LIFF app, the access token will be revoked even if it hasn't expired.

Getting an access token

  • If the user starts the LIFF app in a LIFF browser, the LIFF SDK will get an access token when you call liff.init()

  • If the user starts the LIFF app in an external browser, the LIFF SDK will get an access token when these steps are satisfied:

    1. You call liff.login().
    2. The user logs in.
    3. You call liff.init().

Example

# Syntax

liff.getAccessToken();

# Arguments

None

# Return value

Returns the current user's access token as a string.

# liff.getIDToken()

Get the raw ID token of the current user obtained by the LIFF SDK. An ID token is a JSON Web Token (JWT) that contains user data.

You can use the ID token obtained with this API when sending the user data from the LIFF app to the server. For more information, see Using user data in LIFF apps and servers in the LIFF documentation.

Select a scope

When adding a LIFF app to your channel, select the openid scope. You can't get the ID tokens if you don't select the scope, or the users don't grant permission. The scope selections can be changed in the LIFF tab of the LINE Developers Console even after adding the LIFF app.

Getting an ID token

  • If the user starts the LIFF app in a LIFF browser, the LIFF SDK will get an ID token when you call liff.init()

  • If the user starts the LIFF app in an external browser, the LIFF SDK will get an ID token when these steps are satisfied:

    1. You call liff.login().
    2. The user logs in.
    3. You call liff.init().
You can get the user's email address

To get the email addresses of users, select the email scope when adding a LIFF app to your channel. You will get the email addresses once the users grant permission. The scope selections can be changed in the LIFF tab of the LINE Developers Console even after adding the LIFF app.

Example

# Syntax

liff.getIDToken();

# Argument

None

# Return value

Returns a raw ID token.

# liff.getDecodedIDToken()

Gets the payload of the ID token that's acquired by the LIFF SDK. The payload includes information such as user display name, profile image URL, email address, etc.

Use this method when you want to use the display name of the user in the LIFF app.

Don't send user info to server

Don't send the user data obtained by this method to the server. For more information, see Using user data in LIFF apps and servers in the LIFF documentation.

Select a scope

When adding a LIFF app to your channel, select the openid scope. You can't get the ID tokens if you don't select the scope, or users don't grant permission. The scope selections can be changed in the LIFF tab of the LINE Developers Console even after adding the LIFF app.

Getting an ID token

  • If the user starts the LIFF app in a LIFF browser, the LIFF SDK will get an ID token when you call liff.init()

  • If the user starts the LIFF app in an external browser, the LIFF SDK will get an ID token when these steps are satisfied:

    1. You call liff.login().
    2. The user logs in.
    3. You call liff.init().
You can get the user's email address

To get the email addresses of users, select the email scope when adding a LIFF app to your channel. You will get the email addresses once the users grant permission. The scope selections can be changed in the LIFF tab of the LINE Developers Console even after adding the LIFF app.

Example

# Syntax

liff.getDecodedIDToken();

# Arguments

None

# Return value

Gets the ID token payload.

For more information on ID token payloads, see the Payload section of Get profile information from ID tokens in the Integrate LINE Login documentation.

Example

# liff.permission.query()

Verifies whether the user agrees to grant the specified permission.

Example

# Syntax

liff.permission.query(permission);

# Arguments

permission

String

Required

The permission to be checked. Specify one of the following scopes:

# Return value

Promise object returned.

When Promise is resolved, an object containing the following properties is returned.

state

String

Contains one of the following values:

  • granted: User has consented to the authorization
  • prompt: User hasn't consented to authorization
  • unavailable: Not available because the channel does not have the specified scope

# liff.permission.requestAll()

Displays the "Verification screen" for the permissions requested by LINE MINI Apps.

verification screen

Operating environment of liff.permission.requestAll()

liff.permission.requestAll() only operates on LINE MINI Apps.

To execute this method, you need to turn on Channel consent simplification in advance on the LINE Developers Console. For more information on setting up the Channel consent simplification feature, see The "Channel consent simplification" feature setup of the LINE MINI App documentation.

Make sure that the user has consented to all the permissions before executing this method

If the user has already consented to all the permissions and you execute liff.permission.requestAll(), Promise will be rejected and LiffError will be returned. Therefore, use liff.permission.query() to check whether the user has consented to all the permissions, and execute liff.permission.requestAll() only if the user has unconsented permissions.

Example

# Syntax

liff.permission.requestAll();

# Arguments

None

# Return value

Returns a Promise object.

# Error response

If Channel consent simplification isn't turned on, and the user has already consented to all the permissions, Promise will be rejected and LiffError will be returned.

# Profile

# liff.getProfile()

Gets the current user's profile information.

Don't send user info to server

Don't send the user data obtained by this method to the server. For more information, see Using user data in LIFF apps and servers in the LIFF documentation.

Select a scope

When adding a LIFF app to your channel, select the profile scope. You can't get user profiles if you don't select the scope, or the user doesn't grant permission. The scope selections can be changed in the LIFF tab of the LINE Developers Console even after adding the LIFF app.

Example

# Syntax

liff.getProfile();

# Arguments

None

# Return value

Returns a Promise object.

When the Promise is resolved, the object containing the user's profile information is passed.

userId

String

User ID

displayName

String

Display name

pictureUrl

String

Image URL. This property is not returned if it has not been set by the user.

statusMessage

String

Status message. This property is not returned if it has not been set by the user.

# Error response

When the Promise is rejected, LiffError is passed.

Example

# liff.getFriendship()

Gets the friendship status between a user and a LINE Official Account.

However, you can only get the friendship status between a user and a LINE Official Account that has been linked to the same LINE Login channel to which your LIFF app has been added. To learn how to link a LINE Official Account to a LINE Login channel, see Add a LINE Official Account as a friend when logged in (add friend option) in the LINE Login documentation.

Select a scope

When adding a LIFF app to your channel, select the profile scope. You can't get the friendship statuses if you don't select the scope, or the users don't grant permission. The scope selections can be changed in the LIFF tab of the LINE Developers Console even after adding the LIFF app.

Example

# Syntax

liff.getFriendship();

# Arguments

None

# Return value

Returns a Promise object.

When acquiring the status of friendship, the Promise is resolved and the information about friendship is passed.

friendFlag

Boolean

  • true: The user has added the LINE Official Account as a friend and has not blocked it.
  • Otherwise, false.
# Error response

When the Promise is rejected, LiffError is passed.

Example

# Window

# liff.openWindow()

Opens the specified URL in the LINE's in-app browser or external browser.

Operating environment of liff.openWindow()

Use of liff.openWindow() in an external browser isn't guaranteed.

Executing liff.openWindow() on LINE for iOS and LIFF v2.16.1 or earlier will open URLs with unintended query parameters added to the end of the URL fragment

In LINE for iOS and LIFF v2.16.1 or earlier, if the url property doesn't contain a query parameter (?key=value) but contains a URL fragment (#URL-fragment), a URL with an unintended query parameter added to the end of the URL fragment will be opened.

These are example of URLs opened when executing the liff.openWindow() method

LIFF SDK version url property URL opened
v2.16.1 https://example.com#URL-fragment https://example.com#URL-fragment?is_liff_external_open_window=false
v2.17.0 https://example.com#URL-fragment https://example.com#URL-fragment

Example

# Syntax

liff.openWindow(params);

# Arguments

params

Object

Required

Parameter object

params.url

String

Required

URL. Specify a full URL.

params.external

Boolean

Optional

Whether to open the URL in an external browser. Specify one of the following values. The default value is false.

  • true: Opens the URL in an external browser.
  • false: Opens the URL in the LINE's in-app browser.

# Return value

None

# liff.closeWindow()

Closes the LIFF app.

This method can be used before the LIFF app is initialized

To use the liff.closeWindow() method before the initialization of the LIFF app by liff.init() has finished, your LIFF SDK version must be v2.4.0 or later.

Note

liff.closeWindow() isn't guaranteed to work in an external browser.

Example

# Syntax

liff.closeWindow();

# Arguments

None

# Return value

None

# Message

# liff.sendMessages()

Sends messages on behalf of the user to the chat room where the LIFF app is opened.

To use this feature, the following conditions must be met:

If the conditions aren't met, the liff.sendMessages() method isn't available and user doesn't grant required permissions yet error with error code 403 will occur. The following are examples of cases that cause the error:

You can get the screen type from which the LIFF app is launched using the liff.getContext() method.

Example

# Syntax

liff.sendMessages(messages);

# Arguments

messages

Array of objects

Required

Message objects
Max: 5
You can send the following types of Messaging API messages:

When messages are sent to a chat that includes a LINE Official Account, the LINE Platform sends webhook events to the bot server. When image, video, and audio messages are sent using the liff.sendMessages() method, resulting webhook events contain the contentProvider.type property whose value is external. For more information, see Message event in the Messaging API reference.

# Return value

Returns a Promise object.

  • If the message is sent successfully, the Promise is resolved. No value is passed.
  • If you fail to send the message, the Promise is rejected and LiffError is passed.

# liff.shareTargetPicker()

Displays the target picker (screen for selecting a group or friend) and sends the message created by the developer to the selected target. This message appears to your group or friends as if you had sent it.

Note
We don't retrieve the number of people to whom a user has sent a message using the share target picker

In order to protect user privacy, we neither collect nor provide information on how many people received a message from a user through the share target picker.

Example

# Syntax

liff.shareTargetPicker(messages, options);

# Arguments

messages

Array of objects

Required

Message objects
Max: 5
You can send the following types of Messaging API messages:

options

Object

Optional

Share target picker options

options.isMultiple

Boolean

Optional

Specifies whether or not to allow users to select multiple message recipients through the target picker, using either of these values. The default value is true.

  • true: Users can select multiple recipients from their groups, friends, and chats.
  • false: Users can select only one of their friends as the recipient.
Setting isMultiple to false doesn't guarantee that the message will be sent to only one friend

Even if you set the isMultiple property to false, you can still send a message to multiple users by calling the share target picker multiple times, or by re-sharing the same message to different recipients. To strictly allow a user to send a message to one friend only once, add a restriction when implementing the LIFF app.

Here's an example of sending a message containing a URL and restricting access to the URL.

  1. Give the URL a unique token and send the message.
  2. When the URL in the message is accessed, the server side verifies the token and restricts access by multiple users.

# Return value

Returns a Promise object.

  • If the message is sent correctly, Promise is resolved and an object with these properties will be passed.

    status

    String

    success

  • If the user cancels and closes the target picker before sending the message, Promise is resolved but the object isn't passed.

  • If a problem occurs before the target picker is displayed, Promise is rejected and LiffError is passed. For more information on the LiffError object, see LIFF SDK errors.

Note

In the callback function where Promise has been resolved and rejected, the LIFF app won't work on some devices if the developer uses alert().

# Camera

# liff.scanCodeV2()

Launch the 2D code reader and obtain string. To activate the 2D code reader, turn on Scan QR on the LINE Developers Console.

Operating environments of liff.scanCodeV2()

liff.scanCodeV2() works in these environments.

OS Version LIFF browser External browser
iOS 11-14.2 ❌ ✅ *1
14.3 or later ✅ *2 ✅ *1
Android All versions ✅ *2 ✅ *1
PC All versions ❌ ✅ *1

*1 You can only use web browsers that support WebRTC API (opens new window).

*2 Only available when the screen size of the LIFF browser is Full. For details, see Size of the LIFF browser in the LIFF documentation.

Turn [Scan QR] on to launch the 2D code reader

When Adding a LIFF app to your channel, turn on Scan QR. The Scan QR setting can be updated from the LIFF tab on the LINE Developers Console, even after adding a LIFF app to your channel.

The operation specification of liff.scanCodeV2()

liff.scanCodeV2() internally uses an external library called jsQR (opens new window). Therefore, the 2D code reader to be launched when the liff.scanCodeV2() method is executed depends on the operation specification of jsQR (opens new window). Libraries used may be updated or changed without notice.

Example

# Syntax

liff.scanCodeV2();

# Arguments

None

# Return value

Returns a Promise object.

When the string is read by the 2D code reader, Promise is resolved and the object containing the character string is passed.

value

String

String scanned by the 2D code reader

# Error response

When the Promise is rejected, LiffError is passed.

# liff.scanCode()

liff.scanCode() method deprecated

The traditional liff.scanCode() method has been deprecated. We recommend using the liff.scanCodeV2() method for implementing a 2D code reader.


Starts a 2D code reader and gets the string read by the user. To start the 2D code reader, turn on ScanQR on the LINE Developers Console.

Not available on LINE for iOS

liff.scanCode() works in these environments.

OS Version LIFF browser External browser
iOS All versions ❌ ❌
Android All versions ✅ ❌
PC All versions ❌ ❌

Due to technical issues, liff.scanCode is undefined in LINE for iOS. Use it after confirming that the function exists, as shown in the sample code. To use the 2D code reader with LINE for iOS or external browsers, see liff.scanCodeV2().

Turn [Scan QR] on to launch the 2D code reader

Example

# Syntax

liff.scanCode();

# Arguments

None

# Return value

Returns a Promise object.

When reading a string by a 2D code reader, the Promise is resolved and the object containing the string read is passed.

value

String

String read by the 2D code reader

Get the permanent link of any page in the LIFF app.

Permanent link format:

https://liff.line.me/{liffId}/{path}?{query}#{URL fragment}

Example

liff.permanentLink.createUrlBy(url);

url

String

Required

URL to get the permanent link. Any query parameter can be added to it.

Returns a Promise object.

Returns the string of the permanent link when Promise is resolved.

If the URL to get the permanent link doesn't begin with the URL specified for Endpoint URL on the LINE Developers Console, Promise will be rejected and LiffError will be returned.

For example, if the URL to get the permanent link (e.g. https://example.com/) is above Endpoint URL (e.g. https://example.com/path1?q1=v1), Promise will be rejected.

liff.permanentLink.createUrl() may be deprecated in the next major version update

Due to technical issues, liff.permanentLink.createUrl() may be deprecated in the next major version update. To get the permanent link of the current page, we recommend using liff.permanentLink.createUrlBy().

Gets the permanent link for the current page.

Permanent link format:

https://liff.line.me/{liffId}/{path}?{query}#{URL fragment}

Example

liff.permanentLink.createUrl();

None

Returns the current page's permanent link as a string.

A LiffError exception is thrown if the current page URL doesn't start with the URL specified in Endpoint URL of the LINE Developers console.

# liff.permanentLink.setExtraQueryParam()

liff.permanentLink.setExtraQueryParam() may be deprecated in the next major version update

Due to technical issues, liff.permanentLink.setExtraQueryParam() may be deprecated in the next major version update. To add any query parameter to a permanent link on the current page, we recommend using liff.permanentLink.createUrlBy().

You can add any query parameter to a permanent link on the current page.

Each time you execute liff.permanentLink.setExtraQueryParam(), the query parameters added last time are overwritten.

Delete added query parameters
  • To delete the added query parameters, execute liff.permanentLink.setExtraQueryParam("").
  • The added query parameters will be discarded when the user navigates to another page.

Example

liff.permanentLink.setExtraQueryParam(extraString);

extraString

String

Required

Query parameters to add

None

# Bluetooth plugin

# liff.initPlugins()

Enable the plugins.

For example, if you enable the Bluetooth plugin, you can use the client API (liff.bluetooth.*) provided by the Bluetooth plugin.

Example

# Syntax

liff.initPlugins(pluginNames);

# Arguments

pluginNames

Array of String

Required

Plugin name. Specify one of the following values:

  • bluetooth
    *The Bluetooth plug-in can only be activated on LINE for Android. When using LINE for iOS, activation fails and a FORBIDDEN error is returned.

# Return value

Returns a Promise object.

  • If the plugin is enabled successfully, the Promise is resolved.
  • If you fail to enable the plugin, the Promise is rejected and the error information is passed.

# liff.bluetooth.getAvailability()

Not available on LINE for iOS

Due to a technical issue, liff.bluetooth.getAvailability() has been suspended on LINE for iOS.

Check if the Bluetooth plugin can be used. Call this method to check the following conditions:

  • Bluetooth support for the LIFF app added to your channel is enabled

    Note

    You must enable the Bluetooth® Low Energy function of the LIFF app added to your channel to initialize the Bluetooth plugin.

  • Smartphone has Bluetooth enabled

  • User has accepted the LINE Things Terms of Use

  • If using LINE on Android, user has granted permission to use smartphone location information

Note

Enable the Bluetooth plugin by using liff.initPlugins() beforehand.

Example

# Syntax

liff.bluetooth.getAvailability();

# Arguments

None

# Return value

Returns a Promise object.

When the Bluetooth plugin is checked for availability, the Promise is resolved and a Boolean object indicating whether or not the Bluetooth plugin can be used is passed.

# liff.bluetooth.requestDevice()

Not available on LINE for iOS

Due to a technical issue, liff.bluetooth.requestDevice() has been suspended on LINE for iOS.

Scans the linked device, and acquires the information.

You can use a filter to restrict the devices that receive the advertisement packets.

Note

Make sure you first enable the Bluetooth plugin with liff.initPlugins().

Example

# Syntax

liff.bluetooth.requestDevice(options);

# Arguments

options

Object

Optional

RequestDeviceOptionsobject expressing the filter. Omit to retrieve advertisement packets from all devices.

# Data object
# RequestDeviceOptions object

filters

Array of Object

Required

Array of the LINEBluetoothRequestDeviceFilter object

# LINEBluetoothRequestDeviceFilter object

deviceId

String

Required

Device ID of the device that receives the advertisement packet

# Return value

Returns a Promise object.

When scanning linked devices and acquiring the information, the Promise is resolved and the BluetoothDevice object indicating information about the devices is passed.

# Data object
# BluetoothDevice object

id

String

Required

Device ID

name

String

Optional

device name

gatt

Object

Optional

BluetoothRemoteGATTServer object

watchingAdvertisements

Boolean

Required

Monitoring status of advertisement packet (*)

Method Return value Description
watchAdvertisements Promise <void> Starts the reception of the advertisement packet. (*)
unwatchAdvertisements void Stops the reception of the advertisement packet. (*)
addEventListener void Registers the event listener. You can register the event listener in advertisementreceived event(*) and gattserverdisconnected event.
removeEventListener void Deletes the already-registered event listener. You can delete the event listener registered in advertisementreceived event(*) and gattserverdisconnected event.

(*) These functions are implemented on experiment basis. These functions may be changed or stopped without notice.

# BluetoothRemoteGATTServer object

To communicate with devices, use the BluetoothRemoteGATTServer object that expresses the GATT server (Generic Attribute Profile server).

If Promise is resolved after executing liff.bluetooth.requestDevice(), then BluetoothRemoteGATTServer can be accessed from the gatt property of the BluetoothDevice object.

device

Object

Required

BluetoothDevice object

connected

Boolean

Required

true if connected. false if not connected

Method Return value Description
connect Promise <BluetoothRemoteGATTService> Connects with the device.
disconnect void Disconnects from the GATT server of the device.
getPrimaryService(serviceUUID) Promise <BluetoothRemoteGATTService> Acquires the primary service of the GATT server. Specify a 128-bit UUID as a string in the serviceUUID.
Note: This method does not verify the UUID. The UUID is verified when the characteristics are read or written, and when a notification is started or stopped.
# BluetoothRemoteGATTService object

The BluetoothRemoteGATTService object is used to acquire the characteristics.

device

Object

Required

BluetoothDevice object

uuid

String

Required

GATT Service UUID

Method Return value Description
getCharacteristic(characteristicUUID) Promise <BluetoothRemoteGATTCharacteristic> Acquires the characteristics. Specify a 128-bit UUID as a string in the characteristicUUID.
Note: This method does not verify the UUID. The UUID is verified when the characteristics are read or written, and when a notification is started or stopped.
# BluetoothRemoteGATTCharacteristic object

The BluetoothRemoteGATTCharacteristic object is used to read or write the characteristic of the devices, and also to start or stop a notification.

service

Object

Optional

BluetoothRemoteGATTService object

uuid

String

Required

UUID

value

Object

Optional

DataView object (opens new window)

Method Return value Description
readValue Promise <DataView (opens new window)> Reads the value of the characteristic.
writeValue(value) Promise <void> Writes the ArrayBuffer (opens new window), TypedArray (opens new window), or DataView (opens new window) value to the characteristic.
startNotifications Promise <BluetoothRemoteGATTCharacteristic> Starts the notification of characteristic change.
stopNotifications Promise <BluetoothRemoteGATTCharacteristic> Stops the notification of characteristic change.
addEventListener void Registers the event listener. You can register the event listener in characteristicvaluechangedevent containing the target property.
removeEventListener void Deletes the already-registered event listener. You can delete the event listener registered in characteristicvaluechanged event.
Note

readValue() method, writeValue() method, startNotifications() method, and stopNotifications() method verify the UUID and properties. If a UUID or property that does not exist is specified, an error occurs.

Example

# Events

# advertisementreceived event

If an advertisement packet is received, the advertisementreceived event occurs.

Note

The advertisementreceived event is a function that is implemented on experiment basis. This function may be changed or stopped without notice.

device

Object

Required

BluetoothDevice object

name

String

Optional

device name

rssi

Number

Optional

RSSI

manufacturerData

Object

Optional

Map<Number, DataView>object. Data in which the Company Identifier Code is mapped to the DataView object.

# gattserverdisconnected event

If the Bluetooth connection is disconnected due to various reasons, the gattserverdisconnected event occurs. Be sure to register the event listener.

Example

# characteristicvaluechanged event

If a characteristic is changed, the characteristicvaluechanged event occurs.

# liff.bluetooth.referringDevice

Not available on LINE for iOS

Due to a technical issue, liff.bluetooth.referringDevice has been suspended on LINE for iOS.

When the LIFF app is launched via a device, liff.bluetooth.referringDevice is set to a BluetoothDevice object that indicates device information.

# LIFF plugin

# liff.use()

Activates and initializes LIFF API in the pluggable SDK or a LIFF plugin.

Example of LIFF API in the pluggable SDK

Example of LIFF plugin

# Syntax

liff.use(module, option);

# Arguments

module

Object

Required

A LIFF API module in the pluggable SDK or a LIFF plugin.

If you pass a LIFF API module, you need to instantiate the LIFF API module. For more information, see How to use the pluggable SDK in the LIFF documentation.

If you pass a LIFF plugin and the LIFF plugin is a class, you need to instantiate the LIFF plugin. For more information, see Using a LIFF plugin in the LIFF documentation.

option

Any value

Optional

Value to pass to the LIFF plugin specified by the module property. The value is passed as the second argument of the LIFF plugin's install() method. For more information, see option in the LIFF documentation.

# Return value

Returns the liff object.

# Internationalization

# liff.i18n.setLang()

Specify the language of the text displayed by the LIFF SDK.

Example

# Syntax

liff.i18n.setLang(language);

# Arguments

language

String

Required

Language tag as defined in RFC 5646 (BCP 47) (opens new window). If there is no translation for the specified language tag, en is used as a fallback.

# Return value

Returns a Promise object.

# Error response

When the Promise is rejected, LiffError is passed.

# Others

# liff.createShortcutOnHomeScreen()

Displays a screen for adding a shortcut to your LINE MINI App to the home screen of the user's device.

For more information, see Add a shortcut to your LINE MINI App to the home screen of the user's device in the LINE MINI App documentation.

When to execute the liff.createShortcutOnHomeScreen() method

The liff.createShortcutOnHomeScreen() method should be executed in response to a user action (e.g. tap) on your LINE MINI App so as not to spoil the user experience.

Example

# Conditions of use

To use the liff.createShortcutOnHomeScreen() method, all of the following conditions must be met:

  • It's a LINE MINI App.
  • The LIFF SDK version of the LINI MINI App is v2.23.0 or later.
  • The LINE app version on the user's device is 13.20.0 or later.

# Operating conditions

If the OS of the user's device is iOS, the default browser must be Safari. If the default browser is other than Safari, an error page will be displayed when the liff.createShortcutOnHomeScreen() method is executed.

# Syntax

liff.createShortcutOnHomeScreen(params);

# Arguments

params

Object

Required

Parameter object

params.url

String

Required

URL. You can specify the following URLs:

  • LIFF URL
  • Permanent link
  • The endpoint URL of the LINE MINI App
  • URL that begins with the endpoint URL of the LINE MINI App

# Return value

Returns a Promise object.

When the Add Shortcut screen is displayed, the Promise is resolved. No value is passed.

You can't confirm whether the user has actually added a shortcut to your LINE MINI app to the home screen of the user's device.

# Error response

When the Promise is rejected, LiffError is passed.