ShellsThe SaaS starter for coding agents.
Shell is a SaaS starter for Next.js and Supabase. It boots into a complete working application — sidebar, header, auth, design system — with zero database tables, then hands your coding agent the skills to turn a conversation about your product into its first schema and screens.
Built with
Features
Application shell: a collapsible sidebar with an icon rail, a header that derives its breadcrumb from the route, and a full-bleed page sub-nav whose tabs fold into a select on small screens — with the sidebar's open state kept in a cookie so it never flashes on load
A cross-agent harness: Claude Code and Cursor both boot into the same five skills, with Supabase's official ones version-locked to a hash, an MCP server pointed at your project, and CLAUDE.md and AGENTS.md as the rulebook — not one README and a hope
The /kickoff interview: a skill that asks what you are building, writes the answer to docs/BRIEF.md as durable context, and turns it into your first migration, policies, navigation and screens
Renders on day zero: npm install && npm run dev and the whole app is on screen — no database, no keys, and no setup step between you and the layout you are trying to judge
Auth and session wiring: Supabase SSR clients, a protected-by-default proxy with a public allowlist, and a session resolved on the server before anything paints — so there are no loading gates, against a project with zero tables
One file for navigation: the sidebar is a plain TypeScript array; adding a page is a route plus one entry, and the header title and active highlight both follow from it automatically
Design system: shadcn/ui on Tailwind v4's CSS-first config, one brand orange split into three tokens so contrast holds everywhere, and a three-step surface ladder that makes every component read as a widget on the page
Modern stack: Next.js 16 · React 19 · TypeScript · Tailwind v4 · shadcn/ui · Supabase
FAQ
Before you build
Start with the frame already built.
Buy it once and the whole app renders on your first npm run dev — then hand it to your agent and start on the product.
- Full source, yours to modify and ship
- Unlimited projects, including client work
- Free updates to Shell
One-time payment. Instant access to the source after checkout.