Add LINE as a login method
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Auth.js · Const
Line
Line is Auth.js’s built-in LINE integration. Configure it with LINE OAuth credentials and register the provider with Auth.js to add LINE login.
How it works
Line is a built-in Auth.js OAuth/OIDC provider. Calling it with LINE OAuth credentials returns a provider configuration that Auth.js uses to handle LINE sign-in and its callback.
Syntax
Line(options)Parameters
| Name | Type | Description |
|---|---|---|
options | OAuthUserConfig<P> | Provider options, including LINE OAuth credentials and other OAuth configuration overrides. |
Returns
OAuthConfig<P>
Key points
- Auth.js includes LINE as a ready-made provider rather than requiring a custom OAuth implementation.
- Start by creating a LINE login channel in the LINE Developer Console.
- Enable the web app option under LINE Login and register the Auth.js callback URL.
- The provider supplies standard configuration values, while its options allow application-specific overrides.
- The factory's options parameter is an OAuthUserConfig for the provider profile type.
Common mistakes
- Email is not available automatically; request the Email address permission in the LINE Developer Console.
- The provider uses the OIDC interpretation by default, so account setup should match LINE's OpenID Connect configuration.
Example: Configure LINE with Auth.js
import { Auth } from "@auth/core"
import Line from "@auth/core/providers/line"
const request = new Request(origin)
const response = await Auth(request, {
providers: [
Line({
clientId: process.env.AUTH_LINE_ID,
clientSecret: process.env.AUTH_LINE_SECRET,
}),
],
})Register the built-in LINE provider with the credentials from the LINE Developer Console, then pass it to Auth.js.
When to use it
Supply LINE client credentials
OAuth configuration
Request permitted LINE profile data
Profile access
Override built-in OAuth defaults
Provider customization
Interview questions
QWhat does the Line provider factory accept and return?
The Line function accepts an OAuthUserConfig for a LineProfile and returns an OAuthConfig for that profile. Passing the resulting configuration in Auth.js's providers list enables LINE authentication.
Follow-up: How would you change the built-in settings? Use the provider function's options to override defaults, following Auth.js's built-in OAuth provider customization guidance.
QWhich callback URL must be registered for LINE?
The callback URL shown by the reference page is https://example.com/api/auth/callback/line. The corresponding URL must be configured for the LINE Login channel.
Follow-up: What should be checked if callbacks fail? Confirm that the deployed callback URL exactly matches the URL registered in the LINE Developer Console.
QWhat LINE-side setup is required?
Create a LINE login channel in the LINE Developer Console, activate the web app under LINE Login, and configure its callback URL. The provider can then be registered with a client ID and client secret.
Follow-up: How is email access enabled? Apply for Email address permission under OpenID Connect in the channel's settings.
Related
LineProfileOAuthUserConfigOAuthConfigAuthcustomizing a built-in OAuth provider