Production-ready Next.js starter kit
Everything between “it works” and “it’s safe to go live,” already done. Auth, payments, security, testing, and a design system. Built for Claude Code from the ground up.
Pay once. Own the code. Updates included.
Next.js 16 · Supabase · Stripe · PostHog · Claude Code
FIG_01 · DESIGN SYSTEM
31 accessible components built on Base UI. Structured tokens, consistent patterns, and an interactive viewer to see it all before changing a thing. Need a new component? Claude builds it in your style.

“16 years designing products. Over a year building full-stack with Claude Code, for clients and for my own products. Sinter is everything I learned about going from prototype to production, packaged so you don’t have to learn it the hard way.”
Jonte Edvardson, Founder
PRICING
$249
One-time purchase
Pay once. Own the code. Updates included.
You vibe coded a working app. Maybe with Lovable, maybe Bolt, maybe Claude. It has auth, payments, a database. It works. But past a handful of screens, things unravel. Welcome to the Month 3 Wall. The point where AI-built apps stop scaling and start breaking.
| What works at first | What breaks at scale |
|---|---|
| Auth and payments in minutes | No roles, no access controls, no audit trail. The first enterprise security review kills the deal. |
| Fast iteration on features | Every fix breaks something else. You're burning credits fixing the AI's fixes, not shipping. |
| One database table does everything | Pages take 4 seconds to load. Your serverless bill keeps climbing. |
| Deploy in one click | One bad Friday deploy and your users see a blank screen all weekend. |
| AI generates code quickly | Webhooks crash silently. Payments fail. You find out when customers email, not when your system alerts you. |
01 · INFRASTRUCTURE
Auth, payments, email, security scanning, CI/CD, and a complete design system. Configured, tested, and working together. Run /setup in Claude Code and start building features, not plumbing.
02 · AI COLLABORATION
Curious about Claude Code but not sure where to start? Sinter gives you a real codebase with a complete methodology already built in. Run /think to explore an idea before writing any code. Run /bootstrap to turn a PRD into a GitHub project board. 27 slash commands, 14 specialized agents, and 22 safety hooks give you spec-driven workflows, structured planning, and verification gates that catch hallucinations before they become bugs.
03 · KNOWLEDGE SYSTEM
390+ documented patterns and decisions that teach Claude Code how your project works. Not generic advice, but your conventions, your edge cases, your architecture. When you solve something with /learn, Claude remembers. When you /reflect, it synthesizes what the codebase has learned and suggests improvements. Run /health periodically to audit the architecture. It catches coupling issues, dead exports, and structural debt that accumulates quietly as you ship.
GETTING STARTED
Clone. Connect. Build.
01
Private GitHub access included with purchase. One command.
$ git clone https://github.com/getsinter/sinter.git02
One command. Claude validates your environment, configures the project, connects your services, and verifies the build. Fully interactive, nothing to guess.
/setup03
Run /think to explore a feature idea. Drop in a PRD and /bootstrap turns it into a roadmap with GitHub issues. Or just tell Claude what to build. Pick whatever matches where you are.
/bootstrapWHAT YOU GET
Email/password, magic links, OAuth (Google, GitHub), session management, protected routes, RLS policies
Stripe integration, webhook handling, subscription management, pricing page, customer portal
Resend integration, transactional templates, email verification
Secret scanning, OWASP hardening, OWASP LLM Top 10, CSP headers, CSRF protection, rate limiting
Playwright E2E, Vitest unit tests, AI-assisted test repair, test coverage
30 GitHub Actions workflows, pre-commit hooks, pre-push hooks, automated code review, AI-powered migration review and bundle analysis
30+ accessible components, token-based theming, interactive viewer, dark mode
PostHog integration, event tracking, session replay, funnels, user paths
27 slash commands, 14 specialized agents, 22 safety hooks, verification protocol, constitution, PostHog MCP
390+ micro-lessons, heat ranking, pattern guides, /learn, /reflect, and /health commands
Multi-provider support (OpenAI + Anthropic), prompt caching (90% savings), composable middleware pipeline, streaming, file uploads, rate limiting
next-intl, JSON translation files, locale-aware routing, automatic detection, SEO-friendly alternate URLs
Answered by Claude Code, directly from the codebase.
Have a specific question? Email us →
$249 one-time. Lifetime access to the codebase. Use on unlimited projects.