Payment routing
One checkout, three rails — Stripe Connect, PayPal, crypto — with provider-specific capture, fee, and refund behavior handled behind a single flow.
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Case study · Role: lead engineer
A live jewelry marketplace where real money moves.
A production two-sided marketplace for fine jewelry — buyers, sellers, offers, checkout, three payment rails, payouts, refunds, disputes, and shipping. Delivered as lead engineer on the live platform.
2-sidedbuyers & sellers
3 railsStripe Connect · PayPal · crypto
Full cycleoffer → checkout → payout
Livein production
The problem
Marketplace payments are a system, not a feature.
A jewelry marketplace moves high-value orders between strangers. That means seller onboarding and identity, payment routing across providers, platform fees, refunds that must never double-fire, disputes with evidence flows, shipment states that interact with payment states, and payouts that have to reconcile to the cent. Every one of those has edge cases that only appear under real traffic.
Architecture
Where the money moves.
What was engineered
The load-bearing parts.
Idempotent money ops
Webhook handling, retry-safe captures and refunds, row-level locking on balance changes, and reconciliation paths for every provider.
Offer & order lifecycle
Offers, cart checkout, order states, shipment integration, and the state machine connecting payment status to fulfillment.
Seller payouts
Connected-account onboarding, split payments, platform fees, payout scheduling, and failure recovery.
Admin operations
A role-aware control center for transactions, orders, users, shipments, and records — the operator's daily surface.
Buyer/seller experience
Listings, search, chat, notifications, and post-order flows that keep both sides informed without support tickets.
Screens
The system in use.
Building a marketplace? Start with the payments map.
The fixed-price audit applies the lessons above to your platform — in 5 business days.