How to Build a Marketplace as a Solo Developer

What You're Building

A marketplace connects buyers and sellers. Think Etsy, Fiverr, or Airbnb, but smaller and more focused. You're building the platform that sits in the middle, handles transactions, and takes a cut. It's one of the hardest things to build solo because you have the classic chicken-and-egg problem. Sellers won't join without buyers, buyers won't come without sellers.

I've built two marketplace-style products. The first one failed because I tried to be everything to everyone. The second one worked because I picked an absurdly specific niche and dominated it before expanding. That's the playbook.

Difficulty & Timeline

Recommended Tech Stack

Next.js with Supabase for the database and auth, Stripe Connect for payments. Stripe Connect is non-negotiable here because it handles the split payments between you and your sellers. Building your own payment splitting is a compliance nightmare you don't want.

If you prefer Python, Django with django-allauth and Stripe Connect works just as well. I've used both. Next.js gets you to a prettier frontend faster, Django gives you a more powerful admin panel for managing listings and disputes.

Step-by-Step Plan

Phase 1: Core Platform (Week 1-4)

Build the seller onboarding flow first. Sellers need to create accounts, connect their Stripe accounts (Stripe Connect handles this), and list their products or services. This is the foundation everything else depends on.

Then build the buyer experience. Browsing listings, search with filters, and a clean product detail page. Don't worry about recommendations or fancy algorithms. A simple search with category filters is enough for launch.

Wire up the payment flow. Buyer pays, Stripe takes their cut, you take your platform fee, seller gets the rest. Test this obsessively. Payment bugs will destroy trust faster than anything else.

Phase 2: Trust & Communication (Week 5-8)

Marketplaces live and die on trust. Build a review system so buyers can rate sellers after transactions. Add basic messaging so buyers and sellers can communicate before purchase. Set up email notifications for new orders, messages, and review requests.

The review system doesn't need to be fancy. Star rating plus a text review. But it needs to be real and honest. Don't be tempted to let sellers delete bad reviews. That's how you lose credibility.

Phase 3: Polish & Launch (Week 9-12)

Build a landing page that clearly explains what your marketplace offers and who it's for. Add a seller dashboard showing their sales, earnings, and pending payouts. Polish the search and discovery experience. Add basic analytics so you can track what's working.

Launch with a small group of sellers you've personally recruited. Yes, manually. I messaged about 50 potential sellers individually to get my first 12. It felt tedious but those early sellers became my biggest advocates.

Key Features to Build First

Listing creation and management. Sellers need to create, edit, and manage their listings with images and descriptions.

Search and filters. Buyers need to find what they're looking for quickly. Category filters, price range, and text search cover 90% of use cases.

Stripe Connect payments. Split payments between platform and sellers. Handle refunds and disputes properly from day one.

Reviews and ratings. This is your trust layer. Without it, buyers won't take the risk on unknown sellers.

Messaging. Buyers will have questions before purchasing. A simple in-platform messaging system reduces friction significantly.

Architecture Overview

Frontend (Next.js)
  ├── Buyer pages (browse, search, purchase)
  ├── Seller dashboard (listings, orders, earnings)
  └── Admin panel (disputes, moderation)

Backend (Supabase / Django)
  ├── Users (buyers + sellers)
  ├── Listings (products/services)
  ├── Orders (transactions)
  ├── Reviews (ratings + text)
  ├── Messages (buyer-seller comms)
  └── Payouts (Stripe Connect)

External Services
  ├── Stripe Connect (payments + payouts)
  ├── Cloudflare R2 (image storage)
  └── Resend (transactional emails)

Common Pitfalls

Trying to build for everyone. The #1 killer of solo marketplace projects. Pick a ridiculously specific niche. "Handmade pet accessories" beats "everything marketplace" every single time. You can expand later once you have traction.

Ignoring the supply side. Most solo developers focus entirely on the buyer experience and forget that sellers need to be recruited, onboarded, and supported. Your first 100 sellers are more important than your first 1,000 buyers. Go get them manually.

Building complex payment splitting. Use Stripe Connect. Don't try to build your own escrow system, payment splitting, or payout management. The regulatory and legal implications alone will eat months of your time.

Launching without enough listings. An empty marketplace is a dead marketplace. Have at least 50-100 real listings before you invite buyers. Even if that means listing things yourself or begging friends to create seller accounts.

Overcomplicating the review system. Stars and text. That's it. You don't need verified purchase badges, response systems, or review voting for v1. Keep it simple and honest.

Timeline Estimate

Is This Worth Building?

Yes, but only if you're prepared for the long game. Marketplaces are incredibly hard to get off the ground because of the chicken-and-egg problem. But once they hit critical mass, they're also incredibly defensible. Network effects mean that every new seller makes the platform more valuable for buyers, and vice versa.

The key is starting small. Insanely small. A marketplace for vintage camera lenses in one city. Custom pet portraits. Freelance DevOps consultants. Pick something so specific that you can personally recruit both sides. Then grow from there.