Integrating LINE Login (v2.0) with your web app

This page explains how to integrate LINE Login into your web app. If you don't have an app to integrate LINE Login, you can use a sample app. See Getting started with LINE Login.

Login flow

The LINE Login process for web apps (web login) is based on the OAuth 2.0 authorization code flow.

An overview of the web login flow is shown below. Web apps must implement any part of the login flow that is relevant to them in the flowchart.

Creating a channel

Create a LINE Login channel and configure it for use with a web app.

• Setting a callback URL

Setting a callback URL

After the user has been authenticated and authorized your web app, the authorization code and state are sent to the callback URL.

Set a callback URL from the LINE Login tab of your channel settings in the LINE Developers Console.

You can set more than one callback URL per channel.

Authenticating users and making authorization requests

Initiate the process of authenticating the user with the LINE Platform and authorizing your app.

Redirect the user to an authorization URL when they click the LINE Login button.

Example authorization URL:

https://access.line.me/dialog/oauth/weblogin?response_type=code&client_id=1234567890&redirect_uri=https%3A%2F%2Fexample.com%2Fauth&state=123abc

You can pass the following query parameters to the authorization URL.

User authentication and authorization

Upon being redirected to the authorization URL, the user logs in with their LINE authentication credentials and decides whether to grant your web app the access permissions it has requested.

Example consent screen:

Receiving the authorization code or error response with a web app

The user is redirected to the callback URL once they have completed the authentication and authorization process.

If the user has granted access to your app, an authorization code is returned.

If the user has not granted access to your app, an error response is returned.

Receiving the authorization code

Once the user has been authenticated and has completed the authorization step, they are redirected to the callback URL with these query parameters.

Example URL of the redirect target:

https://example.com/callback?code=b5fd32eacc791df&state=123abc

Receiving an error response

If the user declines to grant the permissions requested by your app, they are redirected to the callback URL with these query parameters:

Example URL of the redirect target:

https://example.com/callback?error_description=The+user+has+denied+the+approval&errorMessage=DISALLOWED&errorCode=417&state=123abc&error=access_denied

Getting an access token with a web app

You can obtain an access token if the state parameter that you receive along with the authorization code from the LINE Platform matches the state parameter that you specified when authenticating the user and making an authorization request.

Sample request:

curl -v -X POST https://api.line.me/v2/oauth/accessToken \
-H 'Content-Type: application/x-www-form-urlencoded' \
-d 'grant_type=authorization_code' \
-d 'code=b5fd32eacc791df' \
-d 'redirect_uri=https%3A%2F%2Fexample.com%2Fauth' \
-d 'client_id=12345' \
-d 'client_secret=d6524edacc8742aeedf98f'

Example response:

{
  "access_token": "bNl4YEFPI/hjFWhTqexp4MuEw5YPs7qhr6dJDXKwNPuLka...",
  "expires_in": 2591977,
  "refresh_token": "8iFFRdyxNVNLWYeteMMJ",
  "scope": "P",
  "token_type": "Bearer"
}

To learn more, see Issuing access tokens in the LINE Login v2.0 API reference.

Next steps

Once you have an access token, you can use it to do the following:

• Manage access tokens (LINE Login v2.0)
• Manage users (LINE Login v2.0)