The Lovable SaaS Starter Kit is a complete, staged build plan for a real multi-tenant SaaS in Lovable. Instead of one giant prompt that produces a demo, you get 12 carefully ordered prompts that build a production-shaped product: design system, a Supabase schema with row level security, authentication, a marketing site with a database-driven pricing page, onboarding, a core product (uptime monitors with plan limits), team invitations, Stripe billing with webhooks, API keys, audit log, email alerts, an admin back office and a launch checklist.

Every prompt was written the way a senior full-stack engineer would brief Lovable: exact behaviors, edge cases, security rules and a verify checklist so you know the step worked before you move on. A Project Knowledge file keeps Lovable consistent across all steps (semantic design tokens, roles stored in a separate table, secrets only in edge functions). The included data-model.sql is reviewed, paste-ready PostgreSQL with RLS policies, security-definer helpers, plan-limit triggers and column-level grants.

A clickable HTML/CSS/JS prototype of the finished app (landing, pricing, login, dashboard, monitors, team, billing, settings) is the visual spec: keep it next to the Lovable preview and steer the build toward it. A built-in pack browser lets you search, copy and tick off every prompt offline. The sample product is uptime monitoring, but the patterns swap cleanly to any B2B SaaS.

Honest note: Lovable is an AI builder, so results vary; the kit maximizes your odds and gives you a checklist to catch drift.