totally agree with the idea of a SaaS boilerplate to ship faster; i've been there trying to bolt auth and billing onto a prototype and it kills momentum. first, map the single core user journey you'll validate on day one - signup, upgrade to paid, the primary action, and the confirmation - then only build the pages and API routes needed for that path. keep integrations stubbed behind feature flags so you can demo and run end-to-end smoke tests before wiring everything, and reuse a basic pricing plus invoice flow so you don't invent that wheel. fwiw i used a starter kit that had auth and payments preconfigured (Vibe Coding Starter Kit) and it saved me about a week of wiring Stripe and email, letting me focus on the product UX.
Payment systems (webhooks, retries, subscription states) are more complex than they look — starter kits reduce mistakes.
Built-in auth + security patterns help avoid common early vulnerabilities.
You ship faster, get user feedback earlier, and focus on your core differentiation.
Good boilerplates also include SEO/content setup, which helps with early distribution.
Core idea: Time spent rebuilding infrastructure is time not spent validating your product.