BidSmart: A Full-Stack Real-Time Online Auction Platform with Automated Lifecycle Management and Role-Based Access Control

Abstract

BidSmart is a full-stack web-based online auction platform designed with a three-tier user architecture (Buyer, Seller, Admin). The system enables verified sellers to create time-based auctions while buyers can browse, bid, and monitor auctions in near real-time. The platform implements an automated auction state machine (UPCOMING → ACTIVE → ENDING_SOON → CLOSED) with scheduled background tasks for state transitions and winner notifications. Key features include JWT-based stateless authentication, role-based access control, KYC-based seller verification with document uploads, a multi-channel notification system, watchlist management, and multi-image auction listings. The backend is built with Java 21, Spring Boot 4, Spring Security 6, PostgreSQL, and Flyway migrations, while the frontend uses React 18 with TypeScript, TanStack React Query for server state management, and Shadcn/UI with Tailwind CSS. The system ensures bid integrity through transactional validation, optimistic concurrency control, and database-level constraints. This paper presents the design, architecture, and implementation of a scalable, secure, and user-friendly auction platform.