line-login-sdks

name: line-login-sdks description: >- LINE Login SDKs official reference at API-reference depth. Covers the native mobile/game SDKs that integrate LINE Login (LINE's OAuth 2.0 / OpenID Connect social login) into apps: the LINE SDK v5 for iOS Swift, the LINE SDK v5 for Android, the LINE SDK for Unity, and the LINE SDK for Flutter plugin. Use this skill whenever the task touches client-side LINE Login on a native app: installing the SDK (CocoaPods LineSDKSwift, Carthage, Maven Central com.linecorp.linesdk:linesdk, Unity .unitypackage, pub.dev flutter_line_sdk), configuring channel ID / bundle ID / package name / URL schemes, calling LINE Login, getting an access token / ID token, getting the user profile, logging users out, refreshing or verifying access tokens, enabling the add friend option (bot prompt) and checking friendship status, handling SDK errors, using universal links on iOS, or using the SDK from Objective-C. Also includes the full per-platform SDK class/method API reference — every class, interface, enum, property, method signature, and parameter for the iOS Swift, Android, Unity, and Flutter SDKs. Trigger on mentions of: LINE Login SDK, LINE SDK for iOS / Swift, LINE SDK for Android, LINE SDK for Unity, LINE SDK for Flutter, LoginManager, LoginManager.shared, LoginManager.Parameters, LoginButton, LoginButtonDelegate, LoginProcess, LoginResult, LoginManagerOptions, LoginPermission, LineSDKError, AccessTokenStore, AccessToken, AccessTokenVerifyResult, API.getProfile, API.getBotFriendshipStatus, API.Auth, UserProfile, JWT, LineLoginApi, LineApiClient, LineApiClientBuilder, LineApiResponse, LineApiResponseCode, LineApiError, LineLoginResult, LineCredential, LineProfile, LineIdToken, LineAccessToken, LineFriendshipStatus, Scope, LoginDelegate, LoginListener, LineAuthenticationParams, LineAuthenticationParams.Builder, BotPrompt, getLoginIntent, getLoginResultFromIntent, onActivityResult, LineSDK.Instance, LineAPI, StoredAccessToken, BotFriendshipStatus, LoginOption, flutter_line_sdk, LineSDK.login, LineSDK.instance, line3rdp. URL scheme, lineauth2, bot prompt, botPromptStyle, friendship status, friendshipStatusChanged, IDTokenNonce, app-to-app login, line-sdk-ios-swift, line-sdk-android, line-sdk-unity. Note: this skill covers the client/native SDK side; the server-side LINE Login v2.1 web API (token exchange endpoints, ID token verification endpoint) is a separate reference.

LINE Login SDKs Reference

API-reference-level coverage of the native LINE Login SDKs, extracted from the official docs section at https://developers.line.biz/en/docs/line-login-sdks/.

These SDKs wrap LINE Login (LINE's OAuth 2.0 + OpenID Connect implementation) for native iOS, Android, Unity, and Flutter apps. They handle the app-to-app / browser login flow, store the access token, and expose typed APIs for profile and token management. Read the reference file that matches the target platform — do not guess class names, method signatures, or scope strings; they differ per platform.

When this skill applies

Any client-side work that integrates LINE Login into a native app via an official SDK: installation, channel linking, performing login, reading the login result, getting the access token / ID token / user profile, logging out, refreshing/verifying tokens, the add friend option, error handling, iOS universal links, or Objective-C interop.

This skill is the client side. The server side — exchanging codes for tokens, the /oauth2/v2.1/* endpoints, the ID token verification endpoint — belongs to the separate LINE Login v2.1 web API reference. The SDKs deliberately push token verification and user-data retrieval to your server (see the "user impersonation" warnings); the SDK hands you an access token / raw ID token string to send to your backend.

Four SDKs — pick the right one

Unity and Flutter are wrappers over the iOS Swift and Android SDKs — they run only on iOS/Android devices, never in Unity Editor play mode or a desktop Flutter target. All four require a LINE Login channel created in the LINE Developers Console.

Reference file map

The skill has two layers: guide files (task-oriented integration steps, crawled from the docs section) and API-reference files (the complete class/method reference, crawled from each SDK's generated API docs). For "how do I do X" read the guide file; for an exact signature / property / enum case read the API-reference file.

Quick SDK index

The core flow is identical across SDKs: configure channel ID → trigger login with a set of scopes → receive a result that carries an access token (and a profile / ID token if those scopes were granted). Token verification and user-data trust must happen on your server, not from the client.

The lists below are an index of the key types — for full signatures, every property, every enum case, and parameter tables, open the matching api-reference-*.md file.

Scopes (login permissions)

iOS SDK for Swift — key types

LoginManager.shared.setup(channelID:universalLinkURL:)   Configure SDK (call first, in didFinishLaunching)
LoginManager.shared.application(_:open:)                  Forward the login callback URL (AppDelegate/SceneDelegate)
LoginManager.shared.login(permissions:in:parameters:completion:)   Start login → Result<LoginResult, LineSDKError>
LoginManager.shared.logout(completion:)                   Invalidate the access token
LoginManager.shared.isAuthorized                          Current login state
LoginManager.Parameters                                   .botPromptStyle (.normal/.aggressive), .IDTokenNonce
LoginButton                                               UIButton subclass; .permissions, .presentingViewController, .delegate
LoginButtonDelegate                                       loginButton(_:didSucceedLogin:) / didFailLogin: / loginButtonDidStartLogin(_:)
LoginResult                                               .accessToken, .permissions, .userProfile, .friendshipStatusChanged
UserProfile                                               .userID, .displayName, .pictureURL, .statusMessage
AccessToken                                               .value, .expiresAt, .IDToken, .IDTokenRaw
AccessTokenStore.shared.current                           The stored AccessToken (or nil)
API.getProfile { }                                        Get UserProfile
API.getBotFriendshipStatus { }                            → .friendFlag
API.Auth.refreshAccessToken { }                           Manual token refresh
API.Auth.verifyAccessToken { }                            → AccessTokenVerifyResult (.channelID, .permissions, .expiresIn)
LineSDKError                                              enum: .requestFailed / .responseFailed / .authorizeFailed / .generalError

Android SDK — key types

LineLoginApi.getLoginIntent(context, channelId, LineAuthenticationParams)            App-to-app login intent
LineLoginApi.getLoginIntentWithoutLineAppAuth(context, channelId, params)            Browser-only login intent
LineLoginApi.getLoginResultFromIntent(data)                                          Parse onActivityResult data → LineLoginResult
LineAuthenticationParams.Builder().scopes(...).nonce(...).botPrompt(...).build()      Login parameters
LineLoginResult                                                                       .getResponseCode(), .getLineProfile(), .getLineCredential(), .getLineIdToken(), .getFriendshipStatusChanged(), .getErrorData()
LineApiClientBuilder(context, channelId).build()  →  LineApiClient                    SDK API client
LineApiClient.getProfile() / getCurrentAccessToken() / refreshAccessToken()           Return LineApiResponse<T>
LineApiClient.verifyToken() / logout() / getFriendshipStatus()
LineApiResponse                                                                       .isSuccess(), .getResponseCode(), .getResponseData(), .getErrorData()
LoginButton (com.linecorp.linesdk.widget)                                             .setChannelId(), .setAuthenticationParams(), .setLoginDelegate(), .addLoginListener()
LoginDelegate.Factory.create()                                                        Delegate wiring for LoginButton
LineCredential / LineAccessToken / LineProfile / LineIdToken                          Result value types

Unity SDK — key types

LineSDK.Instance.Login(string[] scopes, callback)        Start login → Result<LoginResult>
LineSDK.Instance.Login(scopes, LoginOption, callback)    Login with options (BotPrompt, IDTokenNonce, OnlyWebLogin)
LineSDK.Instance.Logout(callback)                        Log out
LineSDK.Instance.SetupSDK()                              Init native side (only if channelID set programmatically)
LineSDK.Instance.CurrentAccessToken                      StoredAccessToken or null (.Value)
LineAPI.GetProfile(callback)                             → UserProfile (.UserId, .DisplayName, .StatusMessage, .PictureUrl)
LineAPI.GetBotFriendshipStatus(callback)                 → BotFriendshipStatus (.IsFriend)
LineAPI.VerifyAccessToken(callback)                      → AccessTokenVerifyResult (.ChannelId, .ExpiresIn, .Scope)
LineAPI.RefreshAccessToken(callback)                     Manual token refresh → AccessToken
LineAPI.RevokeAccessToken(callback)                      Revoke the current access token
result.Match(valueFn, errorFn)                           Handle success/failure; Error has .Code and .Message

Flutter SDK — key types

LineSDK.instance.setup(channelId, {universalLink})       Configure SDK → Future<void>
LineSDK.instance.login({scopes, option})                 Start login → Future<LoginResult>
LineSDK.instance.logout()                                Revoke tokens → Future<void>
LineSDK.instance.getProfile()                            → Future<UserProfile>
LineSDK.instance.getBotFriendshipStatus()                → Future<BotFriendshipStatus> (.isFriend)
LineSDK.instance.verifyAccessToken()                     → Future<AccessTokenVerifyResult>
LineSDK.instance.refreshToken()                          → Future<AccessToken>
LineSDK.instance.currentAccessToken                      → Future<StoredAccessToken?>
LoginResult                                              .accessToken, .userProfile, .scopes, .idTokenNonce, .isFriendshipStatusChanged
LoginOption(onlyWebLogin, botPrompt, {requestCode})      .idTokenNonce settable

Working rules

• Call setup first. iOS: LoginManager.shared.setup(...) must run before any other SDK call (in didFinishLaunching). Android: build a LineApiClient before calling its methods. Unity: the LineSDK prefab must be in the scene.
• Login is async and returns a Result. Switch on success/failure; never assume success. iOS uses Result<LoginResult, LineSDKError>; Android uses LineLoginResult.getResponseCode(); Unity uses Result.Match.
• Never trust client-supplied identity. Don't send a user ID / profile from app to backend as proof of identity — a malicious client can forge it. Send the access token (server verifies it) or the raw ID token string (server verifies it against the ID token verification endpoint with the matching nonce). The SDKs surface accessToken.value / IDTokenRaw / getTokenString() / raw ID token exactly for this.
• Tokens auto-refresh — let them. API-type calls auto-refresh an expired access token; manual refresh is discouraged. A long-expired token fails to refresh and forces a fresh login. On iOS, only API.* methods auto-refresh — API.Auth.* do not.
• Android: never call SDK methods on the main thread. They do network I/O and throw NetworkOnMainThreadException; wrap in AsyncTask/background. Also avoid singleInstance launch mode on the login activity (breaks onActivityResult), and don't use resource IDs prefixed linesdk_.
• iOS: the lineauth2 scheme launches LINE; line3rdp.<bundle id> returns to your app. Put line3rdp.$(PRODUCT_BUNDLE_IDENTIFIER) in CFBundleURLSchemes and lineauth2 in LSApplicationQueriesSchemes — never the reverse.
• Universal links (iOS) are optional but recommended for security; pass the link to LoginManager.setup(channelID:universalLinkURL:) and it must match the console setting.
• The user ID is unique per provider, not globally. The same LINE user has different user IDs under different providers — don't cross-reference it.
• v4 access tokens don't work with v5. Upgrading the iOS/Android SDK to v5 forces every user to log in again.
• ID tokens are issued only at login. To refresh an ID token, log in again; profile data can instead be re-fetched with getProfile.