Building a SaaS product is easy. Building one that scales is hard. Here is the architecture blueprint we use at MetLink for every SaaS engagement.
Frontend: Next.js App Router
The App Router in Next.js 15+ fundamentally changes how you think about data fetching. Server Components handle data, Client Components handle interactivity. This split reduces JavaScript bundle size by 40-60% for most applications.
Backend: FastAPI or tRPC
For data-intensive applications, FastAPI (Python) gives you the performance you need with the AI ecosystem you want. For TypeScript-heavy teams, tRPC eliminates the API layer entirely, type-safe end-to-end.
Database Architecture
The biggest scaling mistake: using a single database for everything.
- PostgreSQL for relational data (Supabase or Neon for serverless)
- Redis for caching and session management
- Pinecone or PgVector for embeddings and semantic search
- S3 or Cloudflare R2 for file storage
Deployment
- Vercel for Next.js frontend
- Railway or Render for backend services
- Cloudflare for CDN and edge functions
- GitHub Actions for CI/CD
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Rahul Mehta
Head of Engineering at MetLink
Expert at MetLink specializing in software development. Helping businesses grow through data, technology, and creative strategy.