Tien Dau

Delivered an end-to-end eCommerce platform for automotive dealerships, including dealer websites, lead management, and vehicle aggregation. Built and maintained integrations with automotive data providers, CRMs, and finance/insurance services, handling undocumented partner APIs, retries, edge cases, and failure paths. Implemented background processing with Sidekiq and Redis for vehicle feed ingestion, data synchronisation, and notification delivery. Delivered features from API design through to responsive React UIs, with test coverage via RSpec and Vitest.

Worked on HotHealth, a digital front door and patient portal for healthcare organisations. Inherited a Rails 4 healthcare application with under 20% test coverage, expanded test coverage above 80%, and upgraded through to Rails 7 and Ruby 3.3 in about 3.5 months without production incidents. Built patient-facing features across patient records, PII, and pre-admission forms, meeting privacy, consent, and healthcare access-control requirements. Improved performance by eliminating N+1 queries, adding covering indexes, and introducing caching; reduced CI/CD pipeline time; and led delivery and mentorship through the Rails upgrade and pre-admission form submission work.

Owned security groups, document management, and the LMS module within a high-traffic HR and payroll platform. Delivered Learning Management System integration with Go1, including negotiating API contracts, handling sync edge cases, and implementing failure handling. Improved query performance by applying indexing and caching strategies to the platform’s hottest paths. Led migration of legacy data to a new PostgreSQL schema with integrity checks to keep cutover clean.