Full-Stack Developer – Build GPT-4o Powered SaaS Web App (ChatGPT Wrapper)

Project Overview:

We are building a professional AI-powered web application using GPT-4o.

This is NOT a simple landing page or hobby project.

The goal is to build a polished, production-ready Micro SaaS product that:
Uses GPT-4o via API
Implements structured responses (JSON format)
Has a clean, modern UI
Includes authentication and user accounts
Includes usage tracking + cost control
Integrates payments (Stripe)
Is deployable and scalable

We are looking for someone who can build this from A–Z.

What You Will Build:

Backend
Node.js backend
GPT-4o API integration
Structured message system (system + user prompts)
Controlled output formatting (JSON schema enforcement)
Rate limiting
Usage metering per user
Basic cost monitoring logic
Secure API key handling
Database integration (Postgres preferred)

Frontend
Modern UI (Next.js preferred, React acceptable)
Clean dashboard layout
Responsive design
Loading states
Error handling UX
Professional app-level polish (not basic template)
Infrastructure
Auth system (Clerk/Auth0/Custom JWT)
Stripe subscription system
Deployment (Vercel / AWS / etc.)
Environment variable security
Production readiness

Tech Stack Preference
Node.js
Next.js (preferred)
React
PostgreSQL
OpenAI GPT-4o API
TailwindCSS
Stripe
If you recommend a better stack, explain why.

Required Skills:
Strong OpenAI API experience
Experience building AI SaaS products
Full-stack development (frontend + backend)
Secure API handling
Database schema design
Payment integration (Stripe)
Deployment experience

Bonus:
Experience with structured GPT outputs (JSON schema)
Cost optimization strategies for LLM usage
Experience building Micro SaaS products

This Is NOT For:
? Prompt engineers only
? WordPress developers
? No-code builders
? Beginner developers

Success Criteria (First 30-90 Days)
Working GPT-4o integration
Clean UI with input/output flow
Auth system live
Stripe subscription live
Usage tracking implemented
Deployed production version

To Apply, Answer ALL of the following:

Describe an AI product you have built using OpenAI.

How would you structure GPT responses to ensure reliable parsing?

How would you prevent OpenAI costs from getting out of control?

What stack would you use for this and why?

Share GitHub and live project links.

Include your expected monthly salary.

Include the word “GPT4O” at the top of your application.

Shortlisted candidates will receive project details.