# Nextauth
> Configure NextAuth.js v5 authentication with OAuth providers and Prisma adapter. Use when setting up login/logout, protecting routes, accessing sessions in components, adding OAuth providers, or troubleshooting authentication issues.
- Skill: `majiayu000/nextauth-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add majiayu000/nextauth-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/nextauth-2/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- License: MIT
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/nextauth-2
---
# NextAuth.js v5 Authentication Guide
NextAuth.js v5 (Auth.js) is the authentication library for FTC Metrics. It uses OAuth providers (Google, Discord, GitHub) with a Prisma database adapter for session persistence.
## Quick Start
### 1. Install Dependencies
```bash
bun add next-auth@beta @auth/prisma-adapter
```
### 2. Create Auth Configuration
Create `src/lib/auth.ts`:
```typescript
import NextAuth from "next-auth";
import { PrismaAdapter } from "@auth/prisma-adapter";
import Google from "next-auth/providers/google";
import Discord from "next-auth/providers/discord";
import GitHub from "next-auth/providers/github";
import { prisma } from "@ftcmetrics/db";
export const { handlers, auth, signIn, signOut } = NextAuth({
adapter: PrismaAdapter(prisma),
providers: [
Google({
clientId: process.env.GOOGLE_CLIENT_ID!,
clientSecret: process.env.GOOGLE_CLIENT_SECRET!,
}),
Discord({
clientId: process.env.DISCORD_CLIENT_ID!,
clientSecret: process.env.DISCORD_CLIENT_SECRET!,
}),
GitHub({
clientId: process.env.GITHUB_CLIENT_ID!,
clientSecret: process.env.GITHUB_CLIENT_SECRET!,
}),
],
pages: {
signIn: "/login",
error: "/login",
},
callbacks: {
async session({ session, user }) {
if (session.user) {
session.user.id = user.id;
}
return session;
},
},
session: {
strategy: "database",
},
});
```
### 3. Create API Route Handler
Create `src/app/api/auth/[...nextauth]/route.ts`:
```typescript
import { handlers } from "@/lib/auth";
export const { GET, POST } = handlers;
```
### 4. Add Session Provider
Create `src/components/providers.tsx`:
```typescript
"use client";
import { SessionProvider } from "next-auth/react";
export function Providers({ children }: { children: React.ReactNode }) {
return {children};
}
```
Wrap your app in `src/app/layout.tsx`:
```tsx
import { Providers } from "@/components/providers";
export default function RootLayout({ children }: { children: React.ReactNode }) {
return (
{children}
);
}
```
## Prisma Schema Requirements
Required models for NextAuth with database sessions:
```prisma
model User {
id String @id @default(cuid())
name String?
email String? @unique
emailVerified DateTime? @map("email_verified")
image String?
createdAt DateTime @default(now()) @map("created_at")
updatedAt DateTime @updatedAt @map("updated_at")
accounts Account[]
sessions Session[]
@@map("users")
}
model Account {
id String @id @default(cuid())
userId String @map("user_id")
type String
provider String
providerAccountId String @map("provider_account_id")
refresh_token String? @db.Text
access_token String? @db.Text
expires_at Int?
token_type String?
scope String?
id_token String? @db.Text
session_state String?
user User @relation(fields: [userId], references: [id], onDelete: Cascade)
@@unique([provider, providerAccountId])
@@map("accounts")
}
model Session {
id String @id @default(cuid())
sessionToken String @unique @map("session_token")
userId String @map("user_id")
expires DateTime
user User @relation(fields: [userId], references: [id], onDelete: Cascade)
@@map("sessions")
}
```
## Environment Variables
Add to `.env`:
```bash
# NextAuth
AUTH_SECRET="generate-with-openssl-rand-base64-32"
# Google OAuth
GOOGLE_CLIENT_ID="your-google-client-id"
GOOGLE_CLIENT_SECRET="your-google-client-secret"
# Discord OAuth
DISCORD_CLIENT_ID="your-discord-client-id"
DISCORD_CLIENT_SECRET="your-discord-client-secret"
# GitHub OAuth
GITHUB_CLIENT_ID="your-github-client-id"
GITHUB_CLIENT_SECRET="your-github-client-secret"
```
Generate AUTH_SECRET:
```bash
openssl rand -base64 32
```
## Session Management Patterns
### Server Components (Recommended)
Use the `auth()` function directly in Server Components:
```tsx
import { auth } from "@/lib/auth";
import { redirect } from "next/navigation";
export default async function DashboardPage() {
const session = await auth();
if (!session?.user) {
redirect("/login");
}
return Welcome, {session.user.name}
;
}
```
### Protected Layouts
Protect entire route groups with layout-level auth:
```tsx
import { auth } from "@/lib/auth";
import { redirect } from "next/navigation";
export default async function ProtectedLayout({
children,
}: {
children: React.ReactNode;
}) {
const session = await auth();
if (!session?.user) {
redirect("/login");
}
return <>{children};
}
```
### Client Components
Use the `useSession` hook in Client Components:
```tsx
"use client";
import { useSession, signOut } from "next-auth/react";
export function UserMenu() {
const { data: session, status } = useSession();
if (status === "loading") {
return Loading...
;
}
if (!session?.user) {
return Sign in;
}
return (
{session.user.name}
);
}
```
### Sign In with Providers
```tsx
"use client";
import { signIn } from "next-auth/react";
export function LoginButtons() {
return (
);
}
```
## Adding User ID to Session
The session callback extends the session with the database user ID:
```typescript
callbacks: {
async session({ session, user }) {
if (session.user) {
session.user.id = user.id;
}
return session;
},
},
```
Access the user ID in components:
```tsx
// Server Component
const session = await auth();
const userId = session?.user?.id;
// Client Component
const { data: session } = useSession();
const userId = session?.user?.id;
```
## OAuth Provider Setup
### Google
1. Go to [Google Cloud Console](https://console.cloud.google.com)
2. Create OAuth 2.0 credentials
3. Add authorized redirect URI: `http://localhost:3000/api/auth/callback/google`
### Discord
1. Go to [Discord Developer Portal](https://discord.com/developers/applications)
2. Create application and OAuth2 credentials
3. Add redirect URI: `http://localhost:3000/api/auth/callback/discord`
### GitHub
1. Go to [GitHub Developer Settings](https://github.com/settings/developers)
2. Create OAuth App
3. Add callback URL: `http://localhost:3000/api/auth/callback/github`
## Common Pitfalls
### Session Not Available
- Ensure `SessionProvider` wraps your entire app in the root layout
- Ensure the API route exists at `app/api/auth/[...nextauth]/route.ts`
### User ID Missing from Session
- Add the session callback to include `user.id`
- When using database strategy, user info comes from the `user` parameter, not `token`
### Database Session Issues
- Ensure Prisma schema matches NextAuth requirements exactly
- Use `onDelete: Cascade` on relations to handle user deletion
- Run `prisma migrate dev` after schema changes
### OAuth Callback Errors
- Verify redirect URIs match exactly in provider console
- Include the full path: `/api/auth/callback/[provider]`
- For production, update URIs to use HTTPS and your domain
### AUTH_SECRET Missing
- Generate with `openssl rand -base64 32`
- Required in production, auto-generated in development
## TypeScript Type Extensions
Extend session types in `src/types/next-auth.d.ts`:
```typescript
import { DefaultSession } from "next-auth";
declare module "next-auth" {
interface Session {
user: {
id: string;
} & DefaultSession["user"];
}
}
```
## File Structure Reference
```
packages/web/src/
lib/
auth.ts # NextAuth configuration
components/
providers.tsx # SessionProvider wrapper
app/
api/auth/[...nextauth]/
route.ts # API route handler
layout.tsx # Root layout with Providers
login/
page.tsx # Login page (server)
login-form.tsx # OAuth buttons (client)
dashboard/
layout.tsx # Protected layout
page.tsx # Uses auth() for session
```
## References
- [NextAuth.js v5 Documentation](https://authjs.dev)
- [Prisma Adapter](https://authjs.dev/getting-started/adapters/prisma)
- [OAuth Providers](https://authjs.dev/getting-started/providers)