How to Build a SaaS with Next.js in 2026 — Complete Starter Guide

Building a SaaS with Next.js in 2026 is straightforward if you choose a clear stack and stick to it. This guide outlines a practical starter: Next.js (App Router), auth, database, billing, and deployment.

## Core Stack

**Framework:** Next.js 14 or 15 (App Router). Use Server Components for data fetching and static bits; Client Components for forms and interactivity.

**Auth:** Use a dedicated provider (Clerk, Auth.js, Supabase Auth, or similar). Avoid rolling your own auth for production. Integrate with your database for user records and sessions.

**Database:** PostgreSQL (e.g. Vercel Postgres, Supabase, Neon). Use an ORM (Prisma or Drizzle) for schema, migrations, and type-safe queries.

**Billing:** Stripe for subscriptions and one-off payments. Implement webhooks for subscription lifecycle (created, updated, cancelled) and store subscription state in your DB.

**Hosting:** Vercel is the default for Next.js. Use serverless functions for API routes and cron if needed. For heavier backends, consider a separate service or Railway/Fly.io.

## Project Structure

- **app/** — Routes (app/dashboard, app/api, app/(auth)/login, etc.).
- **components/** — Reusable UI (forms, layout, modals).
- **lib/** — DB client, auth helpers, Stripe, shared utils.
- **types/** — Shared TypeScript types.

Keep API routes thin: validate input, call lib functions, return JSON. Put business logic in lib so it can be reused and tested.

## Key Flows

**Sign up:** Auth provider handles identity; create user row in DB on first sign-in (e.g. via callback or webhook). Optionally add email verification or invite flow.

**Subscription:** Stripe Checkout or Customer Portal for plan selection. On success, Stripe webhook updates your DB; your app checks subscription status before granting access to paid features.

**Multi-tenancy:** If you have workspaces/teams, add an organization or team table and link users via membership. Enforce tenant isolation in every query.

## Security and Performance

- **Auth:** Protect dashboard and API routes; use middleware for redirects.
- **API:** Rate limit, validate input, and never expose internal IDs or secrets.
- **DB:** Use parameterized queries (ORM does this); avoid raw SQL with user input.
- **Performance:** Use React Server Components and streaming where it helps; add caching (e.g. unstable_cache) for heavy reads.

You do not need a boilerplate to start. Create a Next.js app, add auth and a database, then add Stripe. Iterate from there. This stack scales from MVP to thousands of users if you keep boundaries clear and security in mind.