Start your first AI SaaS. VelocityKit is a Next.js starter for shipping a real SaaS product. Auth, billing, email, analytics, and AI features are already wired together, documented, and tested. Clone it, run one setup wizard, and spend your time on your product instead of the plumbing. It is built for AI-assisted development. The repo carries the context files, prompts, and conventions that make Claude Code and similar tools produce code that fits your codebase, and it ships working AI features so your product starts with them instead of bolting them on later. What's inside Next.js 16.2, React 19.2, TypeScript strict, Tailwind CSS 4.3, shadcn/ui Supabase auth: email and password with verification, TOTP two-factor, and OAuth providers enabled by a single env var Postgres with row level security on every table and an account-scoped data model Stripe Checkout, Customer Portal, and a signature-verified webhook; plans live in Stripe product metadata, so pricing changes without a deploy Recurring, one-time with an access period, and lifetime billing modes, plus per-plan usage limits and a free tier Resend with React Email templates for welcome, verification, password reset, invites, payment failures, and subscription changes; auth emails delivered through the Supabase Send Email Hook Unsubscribe handling and email preferences Config-driven marketing site: landing page sections, pricing with a monthly and yearly toggle, MDX blog, changelog, waitlist mode, cookie consent, sitemap, and generated Open Graph images Dashboard with a complete example feature showing the pattern end to end: migration, RLS policies, server actions, optimistic UI, tests AI features via the Vercel AI SDK with OpenAI or Anthropic (claude-haiku-4-5): task suggestions in the app, AI commit messages, and AI release notes, with per-account token budgets, rate limiting, and cost telemetry PostHog analytics and error tracking, with source maps for readable production stack traces 661 unit tests, Playwright end-to-end tests, GitHub Actions CI, and conventional commits enforced by git hooks An interactive setup wizard that checks your tools, collects your keys, creates your Stripe products, and validates every integration 14 feature prompts (organizations, notifications, API keys, webhooks, file uploads, search, and more) written for AI-assisted development What it is not Accounts are single-user today. The database schema is ready for teams; the UI is yours to build, and a guided prompt for it is included. It is not a hosted service. You bring your own Supabase, Stripe, Resend, and PostHog accounts; their free tiers are enough to launch. Requirements Node.js 20.9 or newer and pnpm macOS or Linux for the setup wizard's optional tool installs; manual setup works on Windows What you get The complete source code A commercial license: build unlimited products for yourself or clients; no reselling the source as a starter kit The docs, reference guides, and AI prompt library in the repo Building more than one product? Millroom is coming.