The original auction portal was built on a technologically outdated PHP platform. While it had served its purpose for years, it was gradually falling short of growing demands for usability, security, and regulatory compliance. The primary driver for modernization was a legislative amendment to the Public Auctions Act, which introduced mandatory electronic registration of all public auctions into the Central Register of Public Auctions operated by the Ministry of Regional Development.

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Our task was a complete rewrite of the portal to meet the requirements of a modern, legally compliant solution while enabling its future development. The goal was to run the system on cloud infrastructure instead of dedicated hardware and software — delivering higher reliability, lower costs, and easier scalability. The scope also included increasing the flexibility of the entire solution to support not only standard English auctions (where the price rises with each bid) but also Dutch auctions (where the starting price gradually decreases and the first bidder to accept it wins the item). Improving the user experience (UX/UI) was equally important, with a particular focus on mobile usability — mobile devices now account for roughly half of all visits to the portal, and that share continues to grow.

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Rewriting a large-scale system built up over years — one layered with old, tangled "spaghetti code" and no documentation — is one of the most demanding disciplines in software development. Projects like this often end in delays, extended downtime, or the need to start over from scratch. In the case of OK Dražby, however, the rewrite went smoothly: no downtime, on budget, and fully functional from day one. That success was preceded by detailed technical analyses, trial migrations, and thorough testing of all critical processes. Any outage would have meant not only financial loss, but also legislative and reputational risk. Extended unavailability of the portal could have seriously threatened the entire business.

Coding Bear built the next generation of the OK Dražby auction portal on modern Java and React technologies. The portal runs on Amazon Web Services (AWS), delivering high availability, scalability, and security. The new solution is fully compliant with legislative requirements while enabling further development of features and integrations.

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Architecture

The portal's architecture consists of two parts: a public-facing section and an administration section. The public part serves bidders, who can search for auctions, register, and participate in real-time online bidding. The administration section is designed for auctioneers and handles the planning, management, and evaluation of auctions — including data exports to systems such as the Central Register of Public Auctions and the Auction Portal of the Czech Chamber of Judicial Executors.

Data migration

The project also involved a demanding migration of more than 50,000 user accounts, including the full history of completed and planned auctions. The data transfer covered not only personal information and permissions, but also all bidding records and associated documents. The migration was completed without any extended downtime — the new portal was deployed fully operational from day one. This migration — combining data integrity, regulatory compliance, and minimal operational disruption — was a critical test of both technical readiness and team coordination.

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The project also addressed performance challenges related to server-side rendering using the Next.js framework. For the bidding itself and its synchronization, we used Server-Sent Events (SSE) technology, which pushes data from the server to all clients over a single persistent HTTP connection. This ensures instant response times and flawless synchronization of bid data across all participants. In auctions, milliseconds matter — any slowdown is unacceptable.

After launch, the development team quickly addressed exceptionally high traffic volumes and automated web scraping. Through configuration adjustments to the production environment and optimization of the AWS infrastructure, stable performance was maintained even under heavy load.