Introduction

You have a SaaS idea. You know it needs auth, billing, a database, and a deployment pipeline. But the gap between "I have an idea" and "I have paying customers" feels enormous. This roadmap breaks that gap into concrete, sequential steps — the exact technical execution path from zero to launched. We use Next.js as the framework because it handles frontend, backend, and deployment in a single codebase, but the principles apply to any modern stack.

Week 1: Foundation (Auth + Database)

Day 1-2: Project setup. Initialize a Next.js 14 App Router project with TypeScript and Tailwind CSS. Set up Prisma with PostgreSQL. Create your initial schema with a User model (id, email, name, image, createdAt, updatedAt). Push to GitHub.

Day 3-4: Authentication. Install NextAuth.js (Auth.js). Configure email/password and Google OAuth providers. Create login, register, and dashboard pages. Add middleware to protect routes. Test the full flow: register, login, access dashboard, logout.

Day 5-7: Database schema expansion. Add the models your SaaS needs: Subscription (stripeCustomerId, stripePriceId, isActive), Project (name, slug, userId), and any domain-specific models. Run prisma db push to sync. Create basic CRUD API routes for each model.

By the end of week 1, you have a working app with authentication and a database. It is not pretty, but it works.

Week 2: Billing (Stripe Integration)

Day 8-9: Stripe setup. Create a Stripe account. Create products and prices in the dashboard. Install the Stripe npm package. Create a checkout session API route that generates a Stripe Checkout URL for a given price ID.

Day 10-11: Webhook handling. Create the webhook route at /api/webhook/stripe. Implement signature verification (use req.text(), not req.json()). Handle three events: checkout.session.completed (mark user as active), customer.subscription.updated (sync subscription status), customer.subscription.deleted (deactivate user). Test with the Stripe CLI.

Day 12-14: Customer portal. Create a portal session API route that generates a Stripe Customer Portal URL. Build a settings page where users can manage their subscription. Add a billing section that shows current plan, next billing date, and a link to the portal.

By the end of week 2, you have a complete billing flow: users can subscribe, manage their subscription, and cancel. Revenue is possible.

Week 3: Core Product (Your Actual SaaS)

This week is where your SaaS becomes unique. The specific features depend on your product, but here is the general pattern:

Day 15-17: Core feature implementation. Build the primary value proposition of your SaaS. If it is a project management tool, build the project creation and task management flow. If it is an analytics dashboard, build the data ingestion and visualization pipeline. Focus on one core feature — do not try to build everything.

Day 18-19: API routes. Expose your core functionality through API routes. Even if you are building a frontend-first product, having API routes means you can add integrations, mobile apps, and automation later.

Day 20-21: UI polish. Apply a design system. Use Tailwind CSS with a consistent color palette, typography, and spacing scale. Build reusable components (Button, Input, Card, Modal). Make it responsive. It does not need to be beautiful — it needs to be functional and consistent.

By the end of week 3, you have a working product that does something valuable.

Week 4: Launch Prep (Deployment + Polish)

Day 22-23: Deployment. Create a Vercel account. Connect your GitHub repository. Configure environment variables (DATABASE_URL, NEXTAUTH_SECRET, STRIPE_SECRET_KEY, etc.). Deploy. Verify the production build works. Set up a custom domain.

Day 24-25: Testing and bug fixing. Walk through every flow as a new user: register, subscribe, use the core feature, manage billing, cancel. Fix every bug you find. Ask a friend to do the same. Fix their bugs too.

Day 26-27: SEO and landing page. Write a clear landing page that explains what your SaaS does, who it is for, and why they should pay for it. Add meta tags, Open Graph images, and a sitemap. Submit to Google Search Console.

Day 28: Launch. Post on Product Hunt, Hacker News, Twitter, and relevant communities. Send an email to your waitlist (if you have one). Activate your first marketing channel.

The Tools You Need (And Nothing More)

Next.js (App Router) — frontend and backend in one codebase. TypeScript — catch bugs before your users do. Prisma — type-safe database access with automatic migrations. PostgreSQL — the database that scales from side project to IPO. Stripe — billing that just works. Vercel — deployment with zero configuration. Tailwind CSS — styling without leaving your components. NextAuth.js — authentication that supports every provider.

That is the entire stack. You do not need Redis until you have 10,000+ concurrent users. You do not need Kubernetes until you have a team of DevOps engineers. You do not need microservices until your monolith becomes too large to reason about.

What Most Founders Get Wrong

They spend weeks on the landing page before building the product. Build the product first — you can always iterate on the landing page. They add features nobody asked for. Ship one core feature that solves one problem well. They optimize for scale on day one. Premature optimization is the root of all evil — ship first, optimize when you have users. They skip billing setup. If you are not charging, you do not have a business. Set up Stripe in week 2.

The Shortcut: Use a Boilerplate

Building auth, billing, and database setup from scratch takes 2-4 weeks. A SaaS boilerplate like BreafIO gives you all of this on day one — pre-configured, tested, and production-ready. You skip weeks of setup and start building your actual product immediately. The free tier gives you auth and database. The Core package ($49) adds Stripe billing, team management, and API keys. The decision is not whether to use a boilerplate — it is how much time you want to spend on plumbing versus product.

After Launch: The First 30 Days

Week 1 post-launch: Monitor everything. Set up error tracking (Sentry), analytics (PostHog or Plausible), and uptime monitoring. Respond to every piece of feedback. Week 2: Iterate based on user feedback. The features your users actually use are different from the features you built. Double down on what works. Week 3: Start marketing. Write blog posts about the problem you solve. Engage in communities where your users hang out. Build in public on Twitter. Week 4: Analyze metrics. Track MRR, churn, activation rate, and NPS. These four numbers tell you everything about the health of your SaaS.

Conclusion

Launching a SaaS is not about having the perfect idea or the perfect tech stack. It is about executing sequentially, shipping fast, and iterating based on real user feedback. Follow this roadmap, and you will have a live, paying SaaS product in 4 weeks. The tools are there. The patterns are established. The only variable is your execution.