Every SaaS boilerplate on the market is Next.js.
I searched for months. ShipFast, Supastarter, LaunchFast — all Next.js + Supabase or Prisma. Nothing for the SvelteKit + FastAPI stack that I actually build production apps with.
So I built one.
The Stack
- Frontend: SvelteKit 5 (runes syntax), Tailwind CSS v4, TypeScript
- Backend: FastAPI, SQLAlchemy async, Pydantic v2
- Auth: JWT tokens, bcrypt, email verification, password reset
- Billing: Stripe subscriptions (3 tiers), customer portal, webhooks
- Database: SQLite (dev) / PostgreSQL (production)
- Email: SMTP/Brevo with HTML templates
- Deploy: Docker multi-stage build, nginx reverse proxy
What's Included
50+ files extracted from two production SaaS apps I run (a construction management platform and an EHCP tracker for parents).
- Multi-tenant authentication with role-based access control (user / admin / superadmin)
- Stripe subscription billing with checkout sessions, webhooks, and customer portal
- Admin dashboard with user management and system stats
- Landing page with animated pricing table
- Dark theme with 6-level surface hierarchy and configurable accent color
- Docker Compose for one-command production deployment
Why SvelteKit + FastAPI?
SvelteKit 5 with runes is genuinely faster to build with than React. $state, $derived, $effect — no useState/useEffect ceremony. The compiled output is smaller and faster.
FastAPI gives you automatic OpenAPI docs, type validation via Pydantic, and async by default. Combined with SQLAlchemy, you get a backend that's both fast to write and fast to run.
Docker ties it together. One docker compose up -d and you have a production-ready app with nginx, SSL, health checks, and security headers.
Free Starter vs Premium
I open-sourced a lite version with JWT auth, dark theme, and Docker deploy:
Free: github.com/Quartalis/sveltekit-fastapi-starter
The premium version adds Stripe billing, admin dashboard, multi-tenancy, email verification, password reset, and RBAC:
Premium: quartalis.co.uk/store/saas-boilerplate
Live Demo
You can see the starter kit running at demo-saas.quartalis.co.uk — try creating an account and logging in.
If you're building SaaS with SvelteKit + FastAPI, I'd love to hear what you'd want in a boilerplate. The premium version is still evolving and I'm adding features based on what developers actually need.
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