Full-Stack SaaS Platform (Next.js & Stripe)

Build a complete subscription SaaS platform with Next.js App Router, Tailwind, PostgreSQL, and Stripe checkout.

Build an end-to-end commercial software product: user onboarding, subscription billing tiers, customer dashboard, API key generation, and webhook processing.

Next.js 14+React Server ComponentsTailwind CSSPrismaPostgreSQLStripe

Functional Requirements

Next.js App Router with Server Components and Server Actions
Stripe Checkout and Customer Portal integration
Stripe Webhook handler with signature verification for automated tier provisioning
Role-based organization workspaces and invite team members

System Architecture

Frontend: Next.js App Router, Tailwind CSS, Lucide Icons

Backend: Next.js Server Actions & API Route Handlers

Database: PostgreSQL with Prisma

Auth: NextAuth / Iron Session / JWT

Step-by-Step Implementation

Stripe Webhook Ingestion Engine

Process checkout.session.completed and customer.subscription.updated events securely.

typescript

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import { headers } from "next/headers";
import Stripe from "stripe";
import { prisma } from "@/lib/prisma";
 
const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!, { apiVersion: "2023-10-16" });
 
export async function POST(req: Request) {
  const body = await req.text();
  const signature = headers().get("Stripe-Signature") as string;
 
  let event: Stripe.Event;
  try {
    event = stripe.webhooks.constructEvent(body, signature, process.env.STRIPE_WEBHOOK_SECRET!);
  } catch (err: any) {
    return new Response(`Webhook Error: ${err.message}`, { status: 400 });
  }
 
  if (event.type === "checkout.session.completed") {
    const session = event.data.object as Stripe.Checkout.Session;
    // Upgrade user subscription tier in database
  }
 
  return new Response("OK", { status: 200 });
}

Rationale: Constructing the event with the cryptographic signature ensures no unauthorized entity can trigger fake subscription updates.

Testing & Quality Guidelines

Use the Stripe CLI to trigger mock webhook events locally (stripe listen --forward-to localhost:3000/api/webhooks).
Verify subscription lifecycle: trial -> active -> past_due -> canceled.

Deployment Instructions

Deploy to Vercel with production environment variables.
Configure production Stripe webhook endpoint with SSL.