Built a marketplace with GPT Engineer?
We'll make it production-ready.
Marketplaces are among the hardest apps to build well because they serve two distinct user types (buyers and sellers) with different needs, handle money flowing between users, and require trust systems. AI tools can scaffold the UI quickly, but the critical backend logic — escrow, disputes, ratings, and split payments — needs careful implementation.
Marketplace challenges in GPT Engineer apps
Building a marketplace with GPT Engineer is a great start — but these challenges need attention before launch.
Payment splitting and payouts
Buyers pay, the platform takes a cut, sellers receive the rest. This requires Stripe Connect or similar — significantly more complex than basic checkout. AI tools rarely implement this correctly, leaving you with manual payout processes.
Two-sided authorization
Sellers can manage their listings but not other sellers'. Buyers can view listings but only manage their own orders. Admins can moderate everything. Three distinct permission levels, all enforced server-side.
Trust and safety
Reviews, ratings, dispute resolution, content moderation, and fraud detection. These are complex systems that AI tools don't generate but that make or break a marketplace.
Search and discovery
Users need to find what they're looking for. Basic database queries won't cut it at scale — you need full-text search, filters, sorting, and potentially geolocation. This requires proper indexing or a dedicated search service.
Real-time communication
Buyers and sellers need to communicate. In-app messaging, notifications, and order status updates require real-time capabilities that AI tools often implement superficially.
Data integrity
Inventory counts, order statuses, payment states, and user balances must be consistent. Race conditions (two buyers purchasing the last item simultaneously) require careful database design.
What we check in your GPT Engineer marketplace
Common GPT Engineer issues we fix
Beyond marketplace-specific issues, these are GPT Engineer patterns we commonly fix.
No authentication system
GPT Engineer generates functional UIs but typically skips authentication entirely. All routes and data are publicly accessible.
Direct database access from client
Some generated apps query databases directly from the frontend without an API layer, exposing database credentials and structure.
Incomplete feature implementations
Features that look complete in the UI but don't actually work end-to-end. Buttons that don't submit, forms that don't save, and links that go nowhere.
Missing error boundaries
A single component error crashes the entire application. No error boundaries or fallback UIs to gracefully handle failures.
Start with a self-serve audit
Get a professional review of your GPT Engineer marketplace at a fixed price.
External Security Scan
Black-box review of your public-facing app. No code access needed.
- OWASP Top 10 vulnerability check
- SSL/TLS configuration analysis
- Security header assessment
- Expert review within 24h
Code Audit
In-depth review of your source code for security, quality, and best practices.
- Security vulnerability analysis
- Code quality review
- Dependency audit
- Architecture review
- Expert + AI code analysis
Complete Bundle
Both scans in one package with cross-referenced findings.
- Everything in both products
- Cross-referenced findings
- Unified action plan
100% credited toward any paid service. Start with an audit, then let us fix what we find.
Frequently asked questions
Can I build a marketplace with GPT Engineer?
GPT Engineer is a great starting point for a marketplace. It handles the initial scaffolding well, but marketplace apps have specific requirements — payment splitting and payouts and two-sided authorization — that need professional attention before launch.
What issues does GPT Engineer leave in marketplace apps?
Common issues include: no authentication system, direct database access from client, incomplete feature implementations. For a marketplace specifically, these issues are compounded by the need for payment splitting and payouts.
How do I make my GPT Engineer marketplace production-ready?
Start with our code audit ($19) to get a clear picture of what needs fixing. For most GPT Engineer-built marketplace apps, the critical path is: security review, then fixing core flow reliability, then deployment. We provide a fixed quote after the audit.
How much does it cost to fix a GPT Engineer-built marketplace?
Our code audit is $19 and gives you a complete report of issues. Fixes start at $199 with our Fix & Ship plan. For larger marketplace projects, we provide a custom fixed quote after the audit — no hourly billing.
Get your GPT Engineer marketplace production-ready
Tell us about your project. We'll respond within 24 hours with a clear plan and fixed quote.