Provider configuration (OAuth, credentials) in NextJS - Mini Project: Build & Apply

Provider configuration (OAuth, credentials) in Next.js

📖 Scenario: You are building a Next.js app that needs user login using OAuth providers like GitHub and Google. You will configure these providers step-by-step to enable authentication.

🎯 Goal: Set up OAuth providers in Next.js using the next-auth library by configuring GitHub and Google providers with client IDs and secrets.

📋 What You'll Learn

Create a Next.js API route for authentication

Add GitHub provider configuration with client ID and secret

Add Google provider configuration with client ID and secret

Export the NextAuth handler with the providers configured

💡 Why This Matters

🌍 Real World

OAuth provider configuration is essential for apps that want to let users log in using popular services like GitHub and Google without managing passwords.

💼 Career

Understanding how to configure OAuth providers in Next.js is a common task for frontend and full-stack developers working on modern web applications.

1

Create NextAuth API route file

Create a file named pages/api/auth/[...nextauth].js and import NextAuth from next-auth. Then export a default function calling NextAuth with an empty providers array.

NextJS

import NextAuth from "next-auth"

export default NextAuth({
  providers: []
})

// Your code here

Hint

Use import NextAuth from "next-auth" and export default NextAuth with providers as an empty array.

2

Add GitHub provider configuration

Import GitHubProvider from next-auth/providers/github. Add a GitHub provider to the providers array with clientId set to process.env.GITHUB_CLIENT_ID and clientSecret set to process.env.GITHUB_CLIENT_SECRET.

NextJS

import NextAuth from "next-auth"
import GitHubProvider from "next-auth/providers/github"

export default NextAuth({
  providers: [
    // Add GitHubProvider here
  ]
})

Hint

Import GitHubProvider and add it inside providers with the correct environment variables.

3

Add Google provider configuration

Import GoogleProvider from next-auth/providers/google. Add a Google provider to the providers array alongside GitHub with clientId set to process.env.GOOGLE_CLIENT_ID and clientSecret set to process.env.GOOGLE_CLIENT_SECRET.

NextJS

import NextAuth from "next-auth"
import GitHubProvider from "next-auth/providers/github"
import GoogleProvider from "next-auth/providers/google"

export default NextAuth({
  providers: [
    GitHubProvider({
      clientId: process.env.GITHUB_CLIENT_ID,
      clientSecret: process.env.GITHUB_CLIENT_SECRET
    }),
    // Add GoogleProvider here
  ]
})

Hint

Import GoogleProvider and add it to the providers array with the correct environment variables.

4

Export NextAuth handler with providers

Ensure the default export calls NextAuth with the providers array containing both GitHubProvider and GoogleProvider configured with their client IDs and secrets.

NextJS

import NextAuth from "next-auth"
import GitHubProvider from "next-auth/providers/github"
import GoogleProvider from "next-auth/providers/google"

// Export NextAuth handler with providers
export default NextAuth({
  providers: [
    GitHubProvider({
      clientId: process.env.GITHUB_CLIENT_ID,
      clientSecret: process.env.GITHUB_CLIENT_SECRET
    }),
    GoogleProvider({
      clientId: process.env.GOOGLE_CLIENT_ID,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET
    })
  ]
})

Hint

Make sure the export default calls NextAuth with both providers inside the providers array.

Practice

1. What is the main purpose of configuring a provider in Next.js authentication setup?

easy

A. To create API routes for fetching data

B. To style the login page with CSS

C. To store user data in a database

D. To connect your app to external login services like Google or GitHub

Solution

1. Step 1: Understand provider role in authentication

   Providers allow your app to use external services for user login, such as Google or GitHub.

2. Step 2: Differentiate from unrelated tasks

   Styling, data storage, and API routes are separate concerns not handled by provider configuration.

3. Final Answer:

   To connect your app to external login services like Google or GitHub -> Option D

4. Quick Check:

   Provider = External login connection [OK]

Hint: Providers link your app to login services like Google [OK]

Common Mistakes:

• Confusing providers with styling or database setup
• Thinking providers handle API data fetching
• Assuming providers store user data directly

2. Which of the following is the correct way to import the GitHub provider in Next.js authentication configuration?

easy

A. import { GitHubProvider } from 'next-auth/providers/github';

B. import GitHubProvider from 'next-auth/providers/github';

C. import GitHub from 'next-auth/providers';

D. import { github } from 'next-auth/providers';

Solution

1. Step 1: Check official import syntax

   The correct import uses default import from 'next-auth/providers/github' as GitHubProvider.

2. Step 2: Eliminate incorrect syntax

   Named imports or wrong paths cause errors; only default import from the specific path is correct.

3. Final Answer:

   import GitHubProvider from 'next-auth/providers/github'; -> Option B

4. Quick Check:

   Default import from provider path = C [OK]

Hint: Use default import from 'next-auth/providers/github' [OK]

Common Mistakes:

• Using named import instead of default import
• Importing from wrong module path
• Misspelling provider name or path

3. Given this Next.js provider configuration snippet, what will be the value of providers[0].id?

import GoogleProvider from 'next-auth/providers/google';

const providers = [
  GoogleProvider({ clientId: process.env.GOOGLE_ID, clientSecret: process.env.GOOGLE_SECRET })
];

medium

A. undefined

B. "GoogleProvider"

C. "google"

D. "googleProvider"

Solution

1. Step 1: Understand provider object structure

   GoogleProvider returns an object with an id property set to "google" (lowercase provider name).

2. Step 2: Check the id property value

   Accessing providers[0].id returns "google" as per NextAuth provider conventions.

3. Final Answer:

   "google" -> Option C

4. Quick Check:

   Provider id for Google = "google" [OK]

Hint: Provider id is lowercase provider name like "google" [OK]

Common Mistakes:

• Expecting the id to be the import name
• Assuming id is undefined or camelCase
• Confusing provider instance with string

4. Identify the error in this Next.js credentials provider configuration:

import CredentialsProvider from 'next-auth/providers/credentials';

export const authOptions = {
  providers: [
    CredentialsProvider({
      name: 'Credentials',
      credentials: {
        username: { label: 'Username', type: 'text' },
        password: { label: 'Password', type: 'password' }
      },
      authorize: async (credentials) => {
        if (credentials.username === 'admin' && credentials.password === '1234') {
          return { id: 1, name: 'Admin' };
        }
        return null;
      }
    })
  ]
};

medium

A. No error, configuration is correct

B. Missing async keyword before authorize function

C. authorize function should return false instead of null on failure

D. Credentials object keys must be strings, not objects

Solution

1. Step 1: Review credentials provider syntax

   The credentials object correctly defines username and password with label and type.

2. Step 2: Check authorize function correctness

   authorize is async, returns user object on success, null on failure, which is valid.

3. Final Answer:

   No error, configuration is correct -> Option A

4. Quick Check:

   Credentials provider config valid = B [OK]

Hint: authorize returns user or null; credentials keys are objects [OK]

Common Mistakes:

• Thinking authorize must return false instead of null
• Confusing credentials keys as strings only
• Missing async on authorize function

5. You want to configure both GitHub OAuth and custom credentials login in Next.js. Which is the correct way to combine these providers in authOptions?

hard

A. Set providers as an array with GitHubProvider and CredentialsProvider inside, each configured properly

B. Use only one provider at a time; combining causes errors

C. Merge GitHub and Credentials provider objects into one before adding to providers array

D. Add GitHubProvider inside credentials object as a nested provider

Solution

1. Step 1: Understand multiple provider setup

   NextAuth supports multiple providers by listing them in the providers array separately.

2. Step 2: Avoid incorrect merging or nesting

   Providers must be separate objects; merging or nesting causes errors.

3. Final Answer:

   Set providers as an array with GitHubProvider and CredentialsProvider inside, each configured properly -> Option A

4. Quick Check:

   Multiple providers = separate objects in array [OK]

Hint: List each provider separately in the providers array [OK]

Common Mistakes:

• Trying to merge providers into one object
• Nesting providers inside credentials config
• Assuming only one provider allowed