The AI-First SaaS Boilerplate That Ships

Stop wrestling with auth flows and webhook handlers. NextStart gives you production-hardened primitives—AI streaming, Prisma ORM, RBAC, mobile APIs, and Stripe subscriptions—so you can focus on what makes your SaaS unique.

import { streamText } from 'ai'

export async function POST(req: Request) {
  const { messages } = await req.json()
  
  const result = streamText({
    model: 'gpt-4',
    messages,
    tools: { getWeather, searchDocs },
    guardrails: { toxicity: 0.8 }
  })
  
  return result.toUIMessageStreamResponse()
}

import { prisma } from '@/lib/db'

export async function getUser(id: string) {
  const user = await prisma.user.findUnique({
    where: { id },
    include: { 
      subscription: true,
      entitlements: true 
    }
  })
  
  return user
}

import { withAuth } from '@/lib/auth'

export const GET = withAuth(
  async (req, { user }) => {
    // JWT verified, user loaded
    if (!user.hasEntitlement('premium')) {
      return forbidden()
    }
    
    return json({ data: await getPremiumData() })
  },
  { requiredRole: 'user' }
)

Everything You Need, Nothing You Don't

Production-hardened integrations that work together seamlessly. No vendor lock-in, clear adapter boundaries.

Vercel AI SDK

Streaming, tool calling, model abstraction, guardrails

Supabase Auth

JWT for web & mobile, RBAC, session management

Prisma + Postgres

Type-safe ORM, migrations, seed scripts, Supabase DB

Stripe

Subscriptions, webhooks, entitlements, proration

Resend

Transactional emails, templates, local preview

Versioned APIs

Mobile-ready REST, JWT verification, rate limits

Built for Production, Not Demos

Every feature is battle-tested and documented. We've solved the hard problems so you don't have to.

Production-Hardened Security

RBAC, entitlements, JWT verification for mobile, rate limiting, and audit logs. Not just auth—real authorization.

Ship Faster, Not Harder

Clear modular architecture with feature modules, not tangled pages. Replaceable adapters mean no vendor lock-in.

Type-Safe End-to-End

TypeScript, Zod validation, Prisma ORM. Catch errors at compile time, not in production.

Testing That Works

Playwright E2E tests, Vitest unit tests, webhook mocks, and realistic fixtures. Test auth and billing flows locally.

Performance by Default

Correct RSC/Server Actions usage, caching strategies documented, edge runtime boundaries respected. No footguns.

Mobile-Ready APIs

Versioned REST APIs with strict JWT verification. Flutter-friendly auth flows. Build web and mobile from one codebase.

Why Developers Choose NextStart

We've learned from the pain points of other boilerplates. Here's what makes NextStart different.

Feature

Other Boilerplates

NextStart

Production-ready auth & RBAC

Mobile-friendly JWT APIs

Stripe webhooks with local testing

AI SDK with streaming & tools

Clear architecture, no spaghetti

Comprehensive test coverage

Replaceable adapters (no lock-in)

Step-by-step documentation

Stop Configuring. Start Shipping.

Join developers who've saved weeks of setup time and shipped production-ready SaaS products faster with NextStart.