Fine.dev + Marketplace

Built a marketplace with Fine.dev?
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.

TypeScriptPythonReactNext.jsNode.js

Marketplace challenges in Fine.dev apps

Building a marketplace with Fine.dev 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 Fine.dev marketplace

Payment flow — Stripe Connect setup, split payments, seller payouts
Authorization — buyer vs seller vs admin permissions enforced server-side
Data integrity — race conditions, inventory management, order state machines
Search performance — indexing, query optimization, full-text search
Real-time features — messaging, notifications, live updates
Content moderation — reported content handling, admin tools
Security — data isolation between sellers, payment security
Mobile responsiveness — marketplace browsing experience on mobile

Common Fine.dev issues we fix

Beyond marketplace-specific issues, these are Fine.dev patterns we commonly fix.

highBugs

Spec interpretation may differ significantly from intent

Fine.dev builds exactly what the specification says, not what you meant. Ambiguous specs lead to technically correct implementations that miss the actual product requirement.

highSecurity

Cross-file changes may miss security implications

When Fine.dev generates features spanning multiple files, security-sensitive changes — new endpoints, auth checks, data access patterns — are spread across the PR without a consolidated security review surface.

mediumTesting

Generated tests may not cover real-world edge cases

Fine.dev writes tests for the happy path and obvious failure cases from the spec. Edge cases not explicitly mentioned — concurrent requests, null inputs, rate limits — are frequently untested.

mediumBugs

Cross-file changes introduce inconsistencies

Large implementations touching many files accumulate subtle inconsistencies — type assumptions that don't hold across modules, different error handling patterns in different files.

Start with a self-serve audit

Get a professional review of your Fine.dev marketplace at a fixed price.

External Security Scan

Black-box review of your public-facing app. No code access needed.

$19
  • OWASP Top 10 vulnerability check
  • SSL/TLS configuration analysis
  • Security header assessment
  • Expert review within 24h
Get Started

Code Audit

In-depth review of your source code for security, quality, and best practices.

$19
  • Security vulnerability analysis
  • Code quality review
  • Dependency audit
  • Architecture review
  • Expert + AI code analysis
Get Started
Best Value

Complete Bundle

Both scans in one package with cross-referenced findings.

$29$38
  • Everything in both products
  • Cross-referenced findings
  • Unified action plan
Get Started

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 Fine.dev?

Fine.dev 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 Fine.dev leave in marketplace apps?

Common issues include: spec interpretation may differ significantly from intent, cross-file changes may miss security implications, generated tests may not cover real-world edge cases. For a marketplace specifically, these issues are compounded by the need for payment splitting and payouts.

How do I make my Fine.dev marketplace production-ready?

Start with our code audit ($19) to get a clear picture of what needs fixing. For most Fine.dev-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 Fine.dev-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 Fine.dev marketplace production-ready

Tell us about your project. We'll respond within 24 hours with a clear plan and fixed quote.

Tell Us About Your App