# Cairn: The Next.js SaaS starter kit for creators & indie founders.

> Next.js SaaS starter kit for creators and indie founders: auth, Stripe billing, a shop for digital products, emails and an English and German site. One-time purchase.

Cairn is a production-ready Next.js starter for creators and micro-founders selling courses, presets, templates or memberships: auth, Stripe billing, a shop for digital products, transactional email and a bold English and German marketing site, with privacy-first defaults. Spend the weekend building your product, not plumbing.

**Price:** €199 · One-time payment · unlimited projects

**Buy:** https://buy.polar.sh/polar_cl_GKS2p7UMtCoWq7sl2e7gUxahXvn0OZYXmVTtW3QCXk1

- **~10 min** from download to running locally
- **EN + DE** site, dashboard and emails
- **0** tracking cookies by default
- **Next.js 16** App Router, React 19, TypeScript

## Everything a SaaS needs on day one

The boring parts done right, so you can start with the part that makes you money.

### Marketing site

- Landing page with hero, features, testimonials, pricing and FAQ
- Shop with product pages for digital products
- MDX blog and contact page
- Light and dark theme

### Authentication

- Email and password, magic link, Google sign-in
- Password reset and email change
- Account deletion
- Powered by Better Auth

### Dashboard

- Sidebar layout with launch checklist
- Purchases, billing and settings
- Data export for your users
- Admin user list

### Payments

- Stripe Checkout for subscriptions, one-time plans and shop products
- Customer portal
- Signed, idempotent webhooks
- hasAccess() helper to gate features

### Email

- Welcome, magic link, password reset and verification
- Receipt and failed-payment emails
- React Email + Resend, in English and German

### SEO

- Metadata helpers and hreflang
- Open Graph images
- Sitemap, robots.txt and JSON-LD

### Developer experience

- One-command setup with seed data and demo accounts
- Validated environment variables
- Postgres via Docker or Docker-free (PGlite)
- Vitest, Playwright and GitHub CI

### Launch guide

- Step-by-step launch roadmap in the README
- Reference tags that jump straight to the right code
- Docs for auth, billing, email, deployment and legal

## Modern, popular and well documented

Next.js 16 · React 19 · TypeScript · Tailwind CSS 4 · shadcn/ui · Postgres + Drizzle · Better Auth · Stripe · Resend · Vitest · Playwright

## Privacy-first defaults, built for European customers

- **No cookie banner needed:** Out of the box, Cairn sets no tracking cookies and loads no third-party scripts. Visitor stats use a cookieless wrapper for Plausible or Umami.
- **English and German built in:** Marketing site, dashboard and every email exist in both languages, with proper hreflang and no locale cookie.
- **GDPR features included:** Users can export their data and delete their account themselves. Fonts are self-hosted.
- **EU hosting friendly:** Works with Postgres in an EU region, for example on Neon or Supabase, and deploys to Vercel or your own server.

## Made for people who want to launch, not configure

### A great fit for

- Creators and micro-founders selling courses, presets, templates or subscriptions
- Developers who want a clean, typed and tested foundation
- Businesses that need an English and German product site
- First-time founders: the launch roadmap explains every step

### Good to know

- You need a Postgres database; free tiers at Neon or Supabase are enough to start.
- Payments run through Stripe, and emails through Resend.
- The legal page templates are a starting point, not legal advice.

## Buy once, build as many projects as you like

One licence covers everything. You get the full source code as a download and in a private GitHub repository.

### You may

- Use Cairn for unlimited projects, personal or commercial
- Build products for clients
- Change the code however you like

### You may not

- Resell or share Cairn itself as a template, starter or boilerplate
- Publish the source code of Cairn publicly

### How you get it

1. Buy Cairn through the secure Polar checkout.
2. Open Polar's customer portal (the link is in your receipt email): download the code as a ZIP file, or connect your GitHub account to get the private repository.
3. Unzip or clone it and run pnpm run setup.

## Questions about Cairn

### Do I need to be a developer?

Basic coding knowledge helps. The README contains a launch roadmap that walks you through every step, from running it on your computer to going live. Experienced developers have it running locally in about ten minutes.

### Can I use Cairn for client projects?

Yes. One licence covers unlimited projects, including products you build for clients. You may not resell Cairn itself as a template.

### Where can I host it?

On Vercel or any server that runs Node.js, plus a Postgres database such as Neon or Supabase in an EU region. The docs cover both Vercel and self-hosting.

### Does it work before I set up Stripe and Resend?

Yes. Without a Resend key, emails are printed in your terminal. Without Stripe keys, everything except checkout and the customer portal works. Add the keys when you're ready.

### Can I get a refund?

Yes, within 14 days of your purchase, as long as you haven't accepted the repository invitation or downloaded the code. After access, you can contact us about defects or other problems, and your statutory rights apply. See our refund policy for details.

### How do I get updates?

Updates are pushed to the private GitHub repository you're invited to after your purchase, so you can pull them like any other change.

### Is Cairn GDPR compliant?

Cairn has privacy-first defaults: no tracking cookies, no third-party scripts, self-hosted fonts, data export and account deletion. Whether your product is compliant also depends on how you use it, and you need your own imprint, privacy policy and terms. The included templates are not legal advice.

## The other starter kits

- [Aven](https://zyloft.eu/en/templates/aven/): Next.js Stripe SaaS boilerplate. For subscription SaaS with a shop: monthly and yearly plans, one-time purchases and shop products with Stripe, plus auth, emails and a sleek dark landing page, in English and German. (€229)
- [Fjord](https://zyloft.eu/en/templates/fjord/): Next.js B2B SaaS starter with docs & AI. For B2B SaaS with a calm, Scandinavian-inspired look: landing page, docs portal with an AI assistant, blog, company pages, accounts and Stripe subscriptions. (€229)

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HTML version: https://zyloft.eu/en/templates/cairn/
Deutsche Version: https://zyloft.eu/templates/cairn/index.md