Better-Auth

Better-Auth Integration

MC-ID is built using better-auth and is fully compatible with it. This guide shows how to add MC-ID as an identity provider in your better-auth application.

Tip

The genericOAuth plugin handles PKCE automatically, so you don’t need to implement it manually.

Installation

npm install better-auth

Configuration

Use the genericOAuth plugin to add MC-ID as a provider:

import { betterAuth } from "better-auth";
import { genericOAuth } from "better-auth/plugins";

export const auth = betterAuth({
// ... your other config
plugins: [
  genericOAuth({
    config: [
      {
        providerId: "mc-id",
        clientId: process.env.MCID_CLIENT_ID!,
        clientSecret: process.env.MCID_CLIENT_SECRET!,
        discoveryUrl: "https://mc-id.com/.well-known/openid-configuration",
        scopes: ["openid", "profile", "email", "connections"],
      }
    ]
  })
]
});

Note

The openid scope is required for OIDC compliance. The plugin uses the discovery URL to automatically configure the authorization, token, and userinfo endpoints.

Available Scopes

See MC-ID Scopes

Client-Side Usage

Once configured, you can trigger the MC-ID login flow:

import { signIn } from "./auth-client";

// Redirect to MC-ID login
signIn("mc-id", { callbackURL: "/dashboard" });

User Data

After authentication, the user object will include the claims from the userinfo endpoint based on the scopes you requested:

{
  "sub": "AaltJ3XUoyDQiqDVk865CILljZBXrjZz",
  "name": "Notch",
  "email": "user@example.com",
  "email_verified": true,
  "accounts": [
    {
      "uuid": "069a79f444e94726a5befca90e38aaf5",
      "primary": true,
      "username": "Notch"
    }
  ],
  "connections": [
    {
      "providerId": "discord",
      "accountId": "123456789012345678"
    }
  ]
}