Frontend Developer at Billingly OÜ / ERPLY

Built and maintained business-critical frontend for invoices, orders, quotes, expense reports, customers, products, warehouses, and payments. Developed data-heavy React/TypeScript screens with reusable components, complex forms and tables, validation, pagination, filtering, bulk actions, and responsive desktop/mobile behavior. Worked directly with SQL and internal query APIs and integrated results into the frontend via REST and GraphQL. Participated in an architectural transition moving query execution from client-side/WASM flows into an API/service layer, adapting integrations and tracing regressions. Implemented and debugged long-running operations using SSE with proper loading/progress/error handling while keeping UI state consistent. Debugged end-to-end production issues across UI, API/query layer, database, and legacy code, tracing value transformations and data-related edge cases. Modernized parts of the UI while working around deprecated internal component libraries; added local