Marketplace Systems
Retro Arcade Game Marketplace
Dec 2024 — Mar 2025A full-stack marketplace built around real-time buyer-seller communication, payment handling, and safer transaction state management.
Spring BootReactWebSocketsPostgreSQLPayPalCI/CD
- Real-time chat with persistence, reconnection handling, and ordering guarantees.
- Payment workflow state machine to handle retries/failures/duplicate callbacks safely.
- Mitigated race conditions via idempotent transaction design.