Every SaaS founder says they want to focus on their product.
Yet most of us spend weeks building the same things over and over.
Authentication.
Billing.
User management.
File uploads.
Email flows.
Admin dashboards.
Database setup.
The list never ends.
After building multiple SaaS products, I realized something frustrating. The first month of development rarely goes into building the actual product. Most of the time is spent creating infrastructure that every SaaS application needs.
So I decided to solve that problem once and for all.
I built a Next.js SaaS boilerplate called Kostra.
The Problem I Kept Running Into
Every new SaaS project started the same way.
Create a Next.js app.
Set up PostgreSQL.
Configure authentication.
Integrate Stripe.
Build onboarding flows.
Configure file storage.
Set up transactional emails.
Create protected routes.
Build an admin area.
By the time everything was working, several weeks had already passed.
The worst part was that none of this work made the product unique.
Customers don't buy your SaaS because you integrated Stripe.
They buy it because of the value your product delivers.
What I Wanted From a SaaS Boilerplate
I wasn't looking for a collection of UI components.
I wanted a production-ready foundation.
Something that could support a real SaaS business.
That meant including:
Next.js App Router
PostgreSQL and Prisma
Authentication and authorization
Stripe subscriptions
Email infrastructure
Cloud storage support
API architecture
User onboarding
Admin functionality
TypeScript support
Most importantly, I wanted a codebase that developers could actually maintain.
Why Architecture Matters
Many starter kits focus on features.
I focused on structure.
As applications grow, poor architecture becomes expensive.
Features become harder to ship.
New developers take longer to onboard.
Bugs become harder to track down.
That's why Kostra uses a layered approach that separates:
UI components
Business logic
Database access
External integrations
API endpoints
This keeps the codebase organized as the product grows.
What Ended Up Inside Kostra
Over time, the boilerplate evolved into a complete SaaS foundation.
Some of the core features include:
- Authentication
- Email and password login
- Google OAuth
- Protected routes
- JWT authentication
- Role-based permissions
- Payments
- Stripe integration
- Subscription support
- Billing workflows
- Webhook handling
- Storage
- AWS S3 support
- Cloudflare R2 support
- Direct file uploads using presigned URLs
- Database
- PostgreSQL
- Prisma ORM
- Migration workflows
- Repository pattern
- Developer Experience
- TypeScript
- Zod validation
- Structured services architecture
- Clear documentation The goal was simple.
Help founders launch faster without creating technical debt.
Lessons Learned Building It
Building a SaaS boilerplate taught me something unexpected.
The difficult part isn't adding features.
The difficult part is creating flexibility.
Every SaaS product has different requirements.
A boilerplate should provide a strong foundation without forcing developers into rigid patterns.
That balance took multiple iterations to get right.
Why I Decided to Share It
Originally, Kostra was an internal tool.
I built it for my own projects.
But after seeing how much time it saved, I realized other founders were facing the same challenges.
Most developers don't need another tutorial on setting up authentication.
They need a reliable starting point that lets them focus on building their product.
That's what Kostra is designed to provide.
Final Thoughts
Building a SaaS is already hard.
Your energy should go into solving customer problems, validating ideas, and improving your product.
Not rebuilding login systems for the tenth time.
If you're planning to launch a SaaS with Next.js, investing in the right foundation can save weeks of development time and countless hours of maintenance later.
That's exactly why I built Kostra.
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