line-liff

name

line-liff

description

LINE Front-end Framework (LIFF) official reference at API-reference depth. Covers the full `liff` JavaScript SDK method reference, the LIFF Server API, LIFF plugins, the pluggable SDK, the LIFF CLI / Create LIFF App tooling, and every step of building, registering, and opening a LIFF app. Use this skill whenever the task touches a LIFF app / LINE in-app web app: initializing the SDK, logging users in, reading the LINE user profile, sending messages on the user's behalf, scanning 2D / QR codes, sharing via the share target picker, or debugging a LIFF browser issue. Trigger on mentions of: LIFF, LINE Front-end Framework, LIFF app, liff.line.me, miniapp.line.me, @line/liff, @line/liff-cli, @line/create-liff-app, liff-inspector, liff-mock, the liff CDN sdk.js, liff.init, liff.ready, liff.id, liff.login, liff.logout, liff.getProfile, liff.getAccessToken, liff.getIDToken, liff.getDecodedIDToken, liff.getContext, liff.getOS, liff.getAppLanguage, liff.getVersion, liff.getLineVersion, liff.isInClient, liff.isLoggedIn, liff.isApiAvailable, liff.getFriendship, liff.requestFriendship, liff.openWindow, liff.closeWindow, liff.sendMessages, liff.shareTargetPicker, liff.scanCode, liff.scanCodeV2, liff.permanentLink.createUrlBy, liff.permanentLink.createUrl, liff.permission.query, liff.permission.getGrantedAll, liff.permission.requestAll, liff.use, liff.i18n.setLang, liff.createShortcutOnHomeScreen, LiffError, the LIFF browser, LIFF-to-LIFF transition, LIFF URL, permanent link, the liff.state / liff.referrer query parameters, the chat_message.write scope, the LIFF Server API (POST/PUT/GET/DELETE /liff/v1/apps), or adding a LIFF app in the LINE Developers Console. Also use it for LINE MINI App work, since the MINI App runs on LIFF and uses the same `liff` SDK.

LINE Front-end Framework (LIFF) Reference

API-reference-level coverage of the LINE Front-end Framework (LIFF), extracted from the official LIFF documentation at https://developers.line.biz/en/docs/liff/ and the two LIFF API reference pages (/en/reference/liff/ for the client SDK, /en/reference/liff-server/ for the Server API).

The content is split into topic-scoped reference files. Read the reference file that matches the task — do not guess method names, argument shapes, scope names, or return-value fields.

When this skill applies

Any work on a LIFF app — a web app (HTML + JavaScript) that runs inside the LINE app's LIFF browser or in an external browser, and talks to the LINE Platform through the liff SDK. This includes:

• Integrating and initializing the SDK (liff.init()), CDN vs npm.
• Logging users in/out, reading the profile / ID token / access token.
• Sending messages on the user's behalf, the share target picker.
• 2D code / QR scanning, opening URLs, closing the LIFF app, permanent links.
• Registering a LIFF app (LINE Developers Console or the Server API).
• Building LIFF apps with the LIFF CLI / Create LIFF App.
• Writing LIFF plugins or using the pluggable SDK to shrink the bundle.

LINE MINI Apps also run on LIFF and use the same liff SDK, so this skill applies to MINI App development too (MINI-App-specific features are noted where they appear, e.g. liff.permission.requestAll(), liff.createShortcutOnHomeScreen()).

Two SDKs, two version lines

SDK	Package / path	Version line	Reference file
LIFF client SDK (liff object)	@line/liff (npm) or https://static.line-scdn.net/liff/edge/2/sdk.js (CDN)	LIFF v2 (latest v2.29.0)	references/liff-api-reference.md
LIFF Server API (REST)	https://api.line.me/liff/v1/apps	API v1 (independent of the SDK version)	references/server-api.md

LIFF v1 reached end-of-life on October 1, 2021 — all v1 CDN paths are dead. Only v2 is supported. The Server API stays at v1 even though the SDK is at v2.

Core mental model

1. A LIFF app is a normal web app. You add it to a LINE Login channel (or a LINE MINI App channel) in the LINE Developers Console, which issues a LIFF ID (1234567890-AbcdEfgh) and a LIFF URL (https://liff.line.me/{liffId}).
2. The web app embeds the LIFF SDK and calls liff.init({ liffId }). Every page load must call liff.init() — even same-app navigations.
3. In the LIFF browser (opened via the LIFF URL inside LINE), liff.init() logs the user in automatically. In an external browser, you must call liff.login() yourself (or pass withLoginOnExternalBrowser: true).
4. After init, the SDK holds the user's access token and ID token; most profile / messaging methods work.

Reference file map

File	Contents
references/getting-started.md	LIFF overview (LIFF browser, view sizes, action button, multi-tab view), creating a provider + channel, trying the LIFF starter app, the development workflow
references/developing-liff-apps.md	Building a LIFF app: SDK integration (CDN edge/fixed paths, npm), liff.init() and the four init rules, calling every LIFF API, OGP tags, close behavior, dev guidelines, LIFF browser vs external/in-app browser differences
references/liff-api-reference.md	The full liff client SDK reference: LiffError, SDK properties, and every method — initialization, environment, authentication, profile, window, message, camera, permanent link, plugin, i18n, others
references/server-api.md	The LIFF Server API (POST/PUT/GET/DELETE /liff/v1/apps): add/update/get-all/delete LIFF apps, request/response schemas, error codes
references/opening-and-versioning.md	Opening a LIFF app: LIFF URL, primary/secondary redirect URLs, the liff.state/liff.referrer query params, LIFF-to-LIFF transition, minimizing the LIFF browser, the LIFF versioning policy & life cycle
references/tooling-and-plugins.md	LIFF CLI (liff-cli), Create LIFF App, LIFF plugin authoring (the install() method, hooks), the pluggable SDK and the module list, LIFF Inspector & LIFF Mock

Quick index — liff client SDK methods

All async methods return a Promise; on rejection a LiffError ({code, message, cause?}) is passed. Methods marked pre-init work before liff.init() resolves.

SDK properties
  liff.id                          LIFF ID string (null until init)
  liff.ready                       Promise that resolves on first init

Initialization
  liff.init(config, ok?, err?)     Initialize. config.liffId required;
                                   config.withLoginOnExternalBrowser optional

Getting environment
  liff.getOS()                     "ios" | "android" | "web"           pre-init
  liff.getAppLanguage()            LINE app language (RFC 5646)        pre-init  [v2.24.0+]
  liff.getLanguage()               navigator.language     DEPRECATED   pre-init
  liff.getVersion()                LIFF SDK version string             pre-init
  liff.getLineVersion()            LINE version string | null          pre-init
  liff.getContext()                {type, userId, viewType, scope, availability, ...}
  liff.isInClient()                true in LIFF browser                pre-init
  liff.isLoggedIn()                true if logged in
  liff.isApiAvailable(apiName)     true if feature usable here

Authentication
  liff.login(loginConfig?)         Log in (external / in-app browser only)
  liff.logout()                    Log out
  liff.getAccessToken()            access token string (valid 12 h)
  liff.getIDToken()                raw ID token (JWT) — needs openid scope
  liff.getDecodedIDToken()         decoded ID token payload — needs openid scope
  liff.permission.getGrantedAll()  → Promise<string[]> of granted scopes
  liff.permission.query(scope)     → Promise<{state}> granted|prompt|unavailable
  liff.permission.requestAll()     show verification screen (LINE MINI App only)

Profile
  liff.getProfile()                → {userId, displayName, pictureUrl?, statusMessage?}
  liff.getFriendship()             → {friendFlag} — needs profile scope
  liff.requestFriendship()         prompt user to add the LINE Official Account  [v2.28.0+]

Window
  liff.openWindow({url, external?})   open URL in in-app / external browser
  liff.closeWindow()               close the LIFF app                  pre-init [v2.4.0+]

Message  (LIFF browser only; chat_message.write scope)
  liff.sendMessages(messages)      send up to 5 messages to the current chat
  liff.shareTargetPicker(messages, options?)  pick targets and share; max 5 msgs

Camera  (turn on "Scan QR" in the console)
  liff.scanCodeV2()                → {value} from a 2D code reader
  liff.scanCode()                  → {value}              DEPRECATED, undefined on iOS

Permanent link
  liff.permanentLink.createUrlBy(url)        → Promise<string>
  liff.permanentLink.createUrl()             → string      may be deprecated
  liff.permanentLink.setExtraQueryParam(s)   add query params  may be deprecated

Plugin / i18n / others
  liff.use(module, option?)        activate a pluggable-SDK module or LIFF plugin  pre-init
  liff.i18n.setLang(language)      set LIFF SDK text language          pre-init
  liff.createShortcutOnHomeScreen({url})  add a home-screen shortcut (verified MINI App)  [v2.23.0+]

Quick index — LIFF Server API

The Server API operates LIFF apps on a LINE Login channel. Auth is Authorization: Bearer {channel access token} (short-lived or stateless token of the LINE Login channel).

POST   https://api.line.me/liff/v1/apps            Add a LIFF app   → {liffId}
PUT    https://api.line.me/liff/v1/apps/{liffId}   Update LIFF app settings (partial)
GET    https://api.line.me/liff/v1/apps            Get all LIFF apps on the channel
DELETE https://api.line.me/liff/v1/apps/{liffId}   Delete a LIFF app

Working rules

• Always call liff.init() on every page load (even SPA navigations). Other SDK methods are not guaranteed to work before init resolves, except the pre-init methods listed above.
• Run liff.init() only at the endpoint URL or below it — not at a higher path. v2.27.2+ logs a console warning when this rule is broken.
• Do URL changes after the liff.init() Promise resolves, never before.
• The primary redirect URL carries access_token=xxx — never send it to analytics. v2.11.0+ strips credentials from the URL once liff.init() resolves.
• liff.getProfile() / liff.getDecodedIDToken() give profile data for display only — never POST that to your server. Send the ID token (liff.getIDToken()) or access token (liff.getAccessToken()) instead and verify it server-side.
• liff.sendMessages() / liff.shareTargetPicker() work only in the LIFF browser and need the chat_message.write scope; they fail with 403 otherwise.
• The access token is valid 12 hours but may be revoked when the LIFF app closes.
• A channel can hold at most 30 LIFF apps.
• The LIFF URL https://liff.line.me/{liffId} opens the LIFF browser inside LINE (universal links / app links). The endpoint URL opens LINE's in-app browser, where LIFF-specific features (messaging, share, scan, view size) are unavailable.