Building a SaaS with Next.js: Complete Template Guide

Next.js has become the go-to framework for building modern SaaS applications. Its server-side rendering capabilities, API routes, and seamless deployment make it perfect for creating scalable, performant SaaS products. In this guide, we'll build a complete SaaS template from the ground up.

Prerequisites

Before we start, make sure you have:

• Node.js 18+ installed
• Basic knowledge of React and TypeScript
• A Stripe account for payments
• A database (PostgreSQL recommended)

Step 1: Setting Up Your Next.js SaaS Project

We'll start by creating a new Next.js project with TypeScript and essential dependencies.

npx create-next-app@latest my-saas-app --typescript --tailwind --eslint --app
cd my-saas-app
npm install @next-auth/prisma-adapter prisma @prisma/client stripe
npm install @radix-ui/react-dropdown-menu @radix-ui/react-dialog
npm install lucide-react class-variance-authority clsx tailwind-merge

Step 2: Implementing Authentication

Authentication is crucial for any SaaS application. We'll use NextAuth.js for a robust, secure authentication system.

Setting up NextAuth.js

// app/api/auth/[...nextauth]/route.ts
import NextAuth from 'next-auth'
import { PrismaAdapter } from "@next-auth/prisma-adapter"
import GoogleProvider from 'next-auth/providers/google'
import { prisma } from '@/lib/prisma'

const handler = NextAuth({
  adapter: PrismaAdapter(prisma),
  providers: [
    GoogleProvider({
      clientId: process.env.GOOGLE_CLIENT_ID!,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET!,
    }),
  ],
  pages: {
    signIn: '/login',
    signUp: '/signup',
  },
})

export { handler as GET, handler as POST }

Step 3: Database Setup with Prisma

Prisma provides type-safe database access and excellent developer experience. We'll set up a schema that supports users, subscriptions, and application data.

// prisma/schema.prisma
model User {
  id            String    @id @default(cuid())
  name          String?
  email         String    @unique
  emailVerified DateTime?
  image         String?
  accounts      Account[]
  sessions      Session[]
  subscription  Subscription?
  createdAt     DateTime  @default(now())
  updatedAt     DateTime  @updatedAt
}

model Subscription {
  id                String @id @default(cuid())
  userId            String @unique
  stripeCustomerId  String @unique
  stripeSubscriptionId String? @unique
  stripePriceId     String?
  stripeCurrentPeriodEnd DateTime?
  user              User   @relation(fields: [userId], references: [id])
}

Step 4: Stripe Integration for SaaS Subscriptions

Implement subscription billing with Stripe's robust payment infrastructure. This includes webhook handling for subscription updates and cancellations.

Step 5: Building the SaaS Dashboard

Create a beautiful, functional dashboard using modern UI components and best practices for SaaS application design.

Step 6: Performance & SEO Optimization

Next.js provides excellent performance out of the box, but there are additional optimizations we can implement for SaaS applications.

Conclusion

Building a SaaS application with Next.js provides excellent performance, developer experience, and scalability. By following this guide, you've learned how to implement:

• Robust authentication and user management
• Subscription billing with Stripe
• Modern dashboard interface
• Type-safe database operations
• Performance and SEO optimizations

The Next.js ecosystem continues to evolve, making it easier than ever to build and deploy production-ready SaaS applications.