TIEN DAU

Senior Full-Stack Developer (May 2023 – Present)

Contributing to the HotHealth platform - a Digital Front Door and Patient Portal for healthcare organisations - by designing scalable, high-performance solutions.

Key Achievements:

• Optimised application performance, reduced response time by 60% (7s → under 3s) through code refactoring and database query optimisation.
• Led the successful upgrade of Ruby on Rails from version 4 to 7 and Ruby from 2.6 to 3.3.1, ensuring full compatibility and performance improvements within 3.5 months.
• Increased test coverage of the HotHealth application from under 20% to over 80%, significantly improving code reliability and maintainability.
• Improved uptime and reliability by enhancing server configurations and implementing comprehensive monitoring and alerting with New Relic and Rollbar.
• Streamlined CI/CD pipelines, reducing deployment time from 11 minutes to under 6 minutes.
• Led cross-functional collaboration to implement the pre-admission form submission feature across integrated platforms.
• Mentored junior developers, improved onboarding efficiency and fostered a culture of collaboration and knowledge sharing.

Tech Stack: Ruby on Rails, PostgreSQL, Minitest, Docker, Bitbucket Pipelines, AWS (S3, EC2, RDS)

Intermediate Full-Stack Developer (April 2020 – May 2023)

Contributed to the Employment Hero platform — a high-traffic HR and payroll management system — by developing and maintaining key modules including security groups, document management, and LMS.

Key Achievements:

• Delivered the Learning Management System (LMS) integration with Go1, enhancing training capabilities across the platform.
• Improved system performance by optimising database queries, reduced query time by 50% (6s → under 3s) and introducing effective caching and indexing strategies.
• Led a complex migration of legacy data to a new PostgreSQL schema, ensuring data integrity and consistency throughout the process.
• Contributed to the development of a mobile application, significantly improving the user experience and delivering a large-scale project on schedule.
• Mentored junior developers, promoting a culture of knowledge sharing and continuous improvement within the team.

Tech Stack: Ruby on Rails, ReactJS, PostgreSQL, Redis, Sidekiq, RSpec, Docker

Full-Stack Developer (Sept 2018 – Feb 2020)

Worked on BACS (a container and vessel management system) and SNIPE (a logistics pricing support tool) to streamline operations in the shipping and logistics sector.

Key Achievements:

• Awarded Best Growth of the Year for outstanding performance and contributions to the team.
• Delivered the BACS system — a comprehensive container and vessel management tool — improving operational efficiency.
• Independently developed a full-featured website from concept to deployment, demonstrating strong full-stack development capabilities.
• Optimised search functionality using Elasticsearch, resulting in significantly faster queries and enhanced user experience.
• Built test suites from the ground up to improve code coverage and QA processes, ensuring consistent, high-quality software delivery.
• Consolidated duplicate pagination gems into a single, reusable gem, streamlining pagination across projects and significantly reducing code complexity and maintenance overhead.

Tech Stack: Ruby on Rails, ReactJS, PostgreSQL, Elasticsearch, RSpec