Build a complete AI-powered business called "ContentEngine" — an automated social media content generation platform for small businesses worldwide.
THE BUSINESS MODEL:
Users subscribe to get AI-generated social media content delivered automatically. Three tiers:
Starter: €29/month — 10 posts per week, 1 platform
Pro: €79/month — 30 posts per week, 3 platforms, custom brand voice
Agency: €199/month — Unlimited posts, 10 platforms, white-label reports, client management
HOW THE AI WORKS:
User signs up and enters their business name, industry, target audience, brand voice (professional, casual, funny, etc.), and selects platforms (Twitter/X, LinkedIn, Instagram, Facebook, TikTok)
The AI generates a full week of platform-optimized posts instantly using OpenAI API
Each post is formatted specifically for the platform (character limits, hashtag strategy, image suggestions)
User can regenerate individual posts, edit, approve, or schedule
The AI learns from user edits to improve future generations
CORE PAGES:
Landing Page (/):
Hero: "AI That Runs Your Social Media — So You Don't Have To"
Animated demo showing AI generating a week of posts in seconds
Pricing table (3 tiers with monthly/yearly toggle, yearly gets 2 months free)
"How It Works" section (3 steps: Tell us about your business → AI generates → You approve and post)
Testimonial section (placeholder quotes, real ones come later)
FAQ accordion
CTA: "Start Free 7-Day Trial"
Signup/Onboarding (/onboarding):
Multi-step wizard:
Step 1: Business name, industry (dropdown of 50+ industries), website URL (optional)
Step 2: Target audience description (textarea with AI-powered suggestions)
Step 3: Brand voice selection (cards: Professional, Casual, Bold, Warm, Funny, Luxury, Minimal — each with description)
Step 4: Platform selection (toggle cards for Twitter, LinkedIn, Instagram, Facebook, TikTok)
Step 5: Select plan (3 tiers with clear feature comparison, default recommended Pro)
Step 6: Stripe checkout
After payment, immediately redirect to dashboard with first AI generation running
Dashboard (/dashboard):
"This Week's Content" grid showing generated posts per platform per day
Each post card shows: platform icon, day, post text, character count, hashtags, "Edit" button, "Regenerate" button, "Approve" toggle
Filter by platform, status (pending, approved, edited)
"Generate Next Week" button (uses OpenAI API)
Calendar view toggle
Brand settings sidebar (edit business info, voice, platforms anytime)
AI Generation Engine (API Route /api/generate):
Takes: business_name, industry, audience, brand_voice, platforms[], previous_edits[]
Uses OpenAI GPT-4o with a carefully crafted system prompt that:
Understands each platform's best practices
Adapts tone to brand voice
Incorporates industry-specific hooks and trends
Creates platform-appropriate hashtag sets
Suggests image concepts (e.g., "Photo of team working remotely with laptops")
Avoids generic AI-sounding language
Learns from previous user edits to refine style
Returns JSON with 7 days of posts per platform requested
Client Management (for Agency tier) (/clients):
Add/manage multiple client accounts
Each client has own brand settings, content calendar, and generation history
White-label option: remove ContentEngine branding from client-facing exports
Bulk generation across all clients
TECH STACK:
Next.js 14 (App Router)
Tailwind CSS (modern, clean design — think Jasper.ai or Copy.ai aesthetic)
Supabase (database, auth, realtime)
Stripe (subscriptions with metered billing for API overages)
OpenAI API (GPT-4o for generation)
Vercel (deployment)
SUPABASE DATABASE SCHEMA (complete SQL):
Table: users
id (uuid, primary key, references auth.users)
business_name (text)
industry (text)
target_audience (text)
brand_voice (text)
platforms (text[]) — array of platform names
plan (text) — 'starter', 'pro', 'agency'
stripe_customer_id (text)
stripe_subscription_id (text)
trial_ends_at (timestamptz)
created_at (timestamptz, default now())
Table: generated_posts
id (uuid, primary key)
user_id (uuid, references users.id)
client_id (uuid, nullable, references clients.id)
platform (text)
day_of_week (text) — 'Monday', 'Tuesday', etc.
content (text)
hashtags (text[])
image_suggestion (text, nullable)
status (text) — 'pending', 'approved', 'edited'
original_content (text) — before edits
edited_content (text, nullable) — after user edits
created_at (timestamptz, default now())
Table: clients (for agency tier)
id (uuid, primary key)
agency_user_id (uuid, references users.id)
business_name (text)
industry (text)
target_audience (text)
brand_voice (text)
platforms (text[])
created_at (timestamptz, default now())
Table: edit_history
id (uuid, primary key)
post_id (uuid, references generated_posts.id)
user_id (uuid, references users.id)
original (text)
edited (text)
created_at (timestamptz, default now())
STRIPE INTEGRATION:
Create subscription products in Stripe: Starter (€29/mo), Pro (€79/mo), Agency (€199/mo)
Yearly pricing: Starter (€290/yr), Pro (€790/yr), Agency (€1,990/yr)
Webhook handler for: checkout.session.completed, customer.subscription.updated, customer.subscription.deleted
On successful subscription, update users table with stripe_customer_id and stripe_subscription_id
7-day free trial on all plans (no charge until trial ends)
OPENAI INTEGRATION:
API route POST /api/generate
System prompt engineered for high-quality, non-generic social media content
Temperature: 0.8 (creative but not random)
Max tokens: 2000 per platform per week
Cache common industry patterns to reduce API costs
Track token usage per user for potential overage billing
CRITICAL SELLING FEATURES FOR THE MARKETPLACE:
"One-click setup" — onboarding takes under 3 minutes
"AI that learns your brand" — edit history feeds back into generation
"Multi-platform native" — each platform gets optimized content, not copy-paste
"Agency-ready" — manage unlimited clients from one dashboard
"White-label exports" — agency users can remove branding
"7-day free trial" — proven conversion model
MRR (Monthly Recurring Revenue) business model — the most valuable type
OUTPUT REQUIREMENTS:
Every single file complete. Zero placeholders. Zero "implement later"
Complete .env.example with OPENAI_API_KEY, SUPABASE_URL, SUPABASE_ANON_KEY, STRIPE_SECRET_KEY, STRIPE_WEBHOOK_SECRET
README.md that doubles as a sales document: feature list, pricing strategy, target market, operational costs (OpenAI API), profit margins, scaling guide
The README must make a potential buyer say "this is a real business, not just code"
DESIGN: Jasper.ai meets Linear. Dark mode optional. Clean typography. Smooth animations. Professional but warm. Purple/indigo primary color (AI industry standard). Mobile-responsive everywhere.