Profile
I have worked in software engineering for more than 15 years. My main areas are backend systems, database performance, and production reliability. At LeadDyno, I work on a platform that records more than 100M visits each day.
Professional experience
LeadDyno: Affiliate-Tracking SaaS
Senior Software Engineer / Remote / Jul 2021 - Present
- Maintain the data layer and investigate performance problems on a platform that records 100M+ visits each day. It connects to more than 40 commerce, payment, CRM, and marketing services.
- Reduced the Shopify app's p95 LCP from 20s to 2.1s. The main problems were render-blocking assets, font delivery, and CDN configuration.
- Set up real-user Core Web Vitals reporting for LCP, FCP, CLS, INP, and TTFB. Reports show p75 and p95 by page, country, and connection type.
- Found that RDS had reached its 12,000-IOPS limit. Query and index changes reduced one enterprise dashboard from 31s to 2.5s and a common query from 3.8s to 31ms.
- Migrated a live 1.9-billion-row activity table with no downtime. RDS storage fell by about 50% to 2TB, and the AWS bill fell by 20%.
- Raised automated test coverage from 22% to 66%. Parallel CI reduced the test run from about 25 minutes to less than 10 minutes.
Technologies
Ruby on Rails, Sidekiq, MongoDB, MySQL, Redis, AWS, Grafana
VoicePing: Real-Time Multilingual WebXR
Software Engineer / Remote / Jan 2021 - Jul 2021
- Worked on shared WebXR tours, live translation, session state, and backend services for large 3D assets.
- Moved the 3D map renderer off the main thread with OpenLayers and OffscreenCanvas so that AR and VR frame rates stayed stable.
Technologies
Node.js, React, MySQL, Firebase / Firestore, Redis, AWS, WebXR
Stealth Startup (NDA)
Founding Engineer / Remote / Jun 2020 - Jan 2021
- Hired and onboarded the company's first six engineers.
- Built a multi-brand booking service for web, iOS, and Android. Row locking and a state machine kept concurrent reservations consistent.
- Led the mobile releases and ran an on-premises k3s cluster with shared logs, metrics, alerts, and dashboards.
Technologies
C# / ASP.NET, TypeScript / Node.js, React / Next.js, PostgreSQL, k3s, Docker
ComPlat - Karlsruhe Institute of Technology
Research Software Engineer / Germany / 2016 - 2020
- Worked on Chemotion ELN and added exact, structure, and substructure search for chemical records.
- Created ChemScanner to read chemical reactions from scientific documents. The Journal of Cheminformatics published the work in 2019.
- Connected the Rails and React interfaces to C/C++ chemistry tools through SWIG.
Technologies
Ruby on Rails, React, Python, C/C++, SWIG, Docker, GitLab CI/CD
Infnis Inc.
Software Engineer (Research) / Seoul, South Korea / 2014 - 2016
- Wrote C++ components, including ARP handling, for the PIUS user-space packet-inspection system.
- The system inspected raw network traffic at close to 10 Gbps and searched it for dangerous patterns.
Technologies
C/C++, Boost
Cargigi (acquired by eBay Motors)
Software Engineer / Ho Chi Minh City / 2012 - 2014
- Built inventory tools for auto-dealer networks.
- Automated bulk Craigslist publishing and added operational reports to the internal CRM.
Technologies
ASP.NET
VNG Corporation
System Engineer / Ho Chi Minh City / 2011 - 2012
- Operated more than 200 dedicated servers for a large Vietnamese MMORPG.
- Wrote tools for log parsing, server maintenance, and internal requests.
Technologies
PHP / CodeIgniter, Zabbix, Shell scripting
Education
Ph.D., Organic Chemistry, Karlsruhe Institute of Technology, Germany / 2016 - 2019
M.Sc., Aerospace Information Engineering, Konkuk University, South Korea / 2014 - 2016
B.Eng., Computer Science and Engineering, Ho Chi Minh City University of Technology, Vietnam / 2006 - 2011