Catawiki is Europe’s leading curated auction marketplace. Every month, 15 million people visit Catawiki to bid on vintage watches, rare comics, classic cars, and fine art.

• Architected performance optimizations for high-traffic Seller API endpoints, eliminating N+1 queries and implementing Redis caching, resulting in a 70% reduction in latency and 40% decrease in server load for critical endpoints during peak traffic.

• Designed and implemented the event-driven architecture for the Seller vertical using Ruby on Rails, Kafka, and MySQL.

• Led the backend delivery for high-visibility initiatives like the Porsche campaign and Seller Verification, coordinating cross-functional technical requirements.

• Engineered a high-throughput Pricing Service handling millions of monthly transactions, managing complex logic for dynamic pricing rules, custom roundings using a DSL, and real-time currency exchange.

• Initiated a quality-first culture, driving unit and integration test coverage from ~5% to ~40% by establishing CI/CD gates and mentoring the team on testing best practices.

• Refactored legacy codebases using Domain-Driven Design (DDD), significantly reducing technical debt and decoupling complex business logic to accelerate feature velocity.

• Bootstrapped a modern Order Management System using TypeScript (NestJS) and Prisma, establishing the architectural pattern for future microservices.

• Standardized engineering workflows by conducting workshops on Atomic Git Commits and structured code reviews, improving collaboration and code maintainability across the organization.

• Led the platform migration of the French market business (travaux.com) to the core Instapro platform, enabling rapid expansion into new international markets.

• Designed and implemented business logic on the GraphQL API using DomainDriven Design (DDD), CQRS, and Hexagonal Architecture, ensuring a decoupled and testable codebase.

• Developed internal developer tooling, including a CLI for generating boilerplate code, which standardized project structures and improved team development velocity

• Engineered a multi-provider hotel booking engine from scratch using Symfony 4, MySQL, and Elasticsearch, integrating disparate third-party APIs into a unified, high-speed search experience.

• Led and mentored a team of 5 engineers, overseeing architectural decisions, sprint planning, and code quality standards for the core API team.

• Led the system’s Internationalization (i18n) strategy, re-architecting the backend to support multiple currencies, languages, and country-specific pricing, facilitating growth into 140+ countries.

• Architected a modular payment gateway system, integrating multiple third-party providers to increase payment success rates and boost overall conversion.